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/capability.h>
  22 #include <linux/backing-dev.h>
  23 #include <linux/hugetlb.h>
  24 #include <linux/pagevec.h>
  25 #include <linux/quotaops.h>
  26 #include <linux/slab.h>
  27 #include <linux/dnotify.h>
  28 #include <linux/statfs.h>
  29 #include <linux/security.h>
  30
  31 #include <asm/uaccess.h>
  32
  33 /* some random number */
  34 #define HUGETLBFS_MAGIC 0x958458f6
  35
  36 static struct super_operations hugetlbfs_ops;
  37 static struct address_space_operations hugetlbfs_aops;
  38 const struct file_operations hugetlbfs_file_operations;
  39 static struct inode_operations hugetlbfs_dir_inode_operations;
  40 static struct inode_operations hugetlbfs_inode_operations;
  41
  42 static struct backing_dev_info hugetlbfs_backing_dev_info = {
  43         .ra_pages       = 0,    /* No readahead */
  44         .capabilities   = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
  45 };
  46
  47 int sysctl_hugetlb_shm_group;
  48
  49 static void huge_pagevec_release(struct pagevec *pvec)
  50 {
  51         int i;
  52
  53         for (i = 0; i < pagevec_count(pvec); ++i)
  54                 put_page(pvec->pages[i]);
  55
  56         pagevec_reinit(pvec);
  57 }
  58
  59 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
  60 {
  61         struct inode *inode = file->f_dentry->d_inode;
  62         struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
  63         loff_t len, vma_len;
  64         int ret;
  65
  66         if (vma->vm_pgoff & (HPAGE_SIZE / PAGE_SIZE - 1))
  67                 return -EINVAL;
  68
  69         if (vma->vm_start & ~HPAGE_MASK)
  70                 return -EINVAL;
  71
  72         if (vma->vm_end & ~HPAGE_MASK)
  73                 return -EINVAL;
  74
  75         if (vma->vm_end - vma->vm_start < HPAGE_SIZE)
  76                 return -EINVAL;
  77
  78         vma_len = (loff_t)(vma->vm_end - vma->vm_start);
  79
  80         mutex_lock(&inode->i_mutex);
  81         file_accessed(file);
  82         vma->vm_flags |= VM_HUGETLB | VM_RESERVED;
  83         vma->vm_ops = &hugetlb_vm_ops;
  84
  85         ret = -ENOMEM;
  86         len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
  87         if (!(vma->vm_flags & VM_WRITE) && len > inode->i_size)
  88                 goto out;
  89
  90         if (vma->vm_flags & VM_MAYSHARE)
  91                 if (hugetlb_extend_reservation(info, len >> HPAGE_SHIFT) != 0)
  92                         goto out;
  93
  94         ret = 0;
  95         hugetlb_prefault_arch_hook(vma->vm_mm);
  96         if (inode->i_size < len)
  97                 inode->i_size = len;
  98 out:
  99         mutex_unlock(&inode->i_mutex);
 100
 101         return ret;
 102 }
 103
 104 /*
 105  * Called under down_write(mmap_sem).
 106  */
 107
 108 #ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
 109 unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 110                 unsigned long len, unsigned long pgoff, unsigned long flags);
 111 #else
 112 static unsigned long
 113 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 114                 unsigned long len, unsigned long pgoff, unsigned long flags)
 115 {
 116         struct mm_struct *mm = current->mm;
 117         struct vm_area_struct *vma;
 118         unsigned long start_addr;
 119
 120         if (len & ~HPAGE_MASK)
 121                 return -EINVAL;
 122         if (len > TASK_SIZE)
 123                 return -ENOMEM;
 124
 125         if (addr) {
 126                 addr = ALIGN(addr, HPAGE_SIZE);
 127                 vma = find_vma(mm, addr);
 128                 if (TASK_SIZE - len >= addr &&
 129                     (!vma || addr + len <= vma->vm_start))
 130                         return addr;
 131         }
 132
 133         start_addr = mm->free_area_cache;
 134
 135         if (len <= mm->cached_hole_size)
 136                 start_addr = TASK_UNMAPPED_BASE;
 137
 138 full_search:
 139         addr = ALIGN(start_addr, HPAGE_SIZE);
 140
 141         for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
 142                 /* At this point:  (!vma || addr < vma->vm_end). */
 143                 if (TASK_SIZE - len < addr) {
 144                         /*
 145                          * Start a new search - just in case we missed
 146                          * some holes.
 147                          */
 148                         if (start_addr != TASK_UNMAPPED_BASE) {
 149                                 start_addr = TASK_UNMAPPED_BASE;
 150                                 goto full_search;
 151                         }
 152                         return -ENOMEM;
 153                 }
 154
 155                 if (!vma || addr + len <= vma->vm_start)
 156                         return addr;
 157                 addr = ALIGN(vma->vm_end, HPAGE_SIZE);
 158         }
 159 }
 160 #endif
 161
 162 /*
 163  * Read a page. Again trivial. If it didn't already exist
 164  * in the page cache, it is zero-filled.
 165  */
 166 static int hugetlbfs_readpage(struct file *file, struct page * page)
 167 {
 168         unlock_page(page);
 169         return -EINVAL;
 170 }
 171
 172 static int hugetlbfs_prepare_write(struct file *file,
 173                         struct page *page, unsigned offset, unsigned to)
 174 {
 175         return -EINVAL;
 176 }
 177
 178 static int hugetlbfs_commit_write(struct file *file,
 179                         struct page *page, unsigned offset, unsigned to)
 180 {
 181         return -EINVAL;
 182 }
 183
 184 static void truncate_huge_page(struct page *page)
 185 {
 186         clear_page_dirty(page);
 187         ClearPageUptodate(page);
 188         remove_from_page_cache(page);
 189         put_page(page);
 190 }
 191
 192 static void truncate_hugepages(struct inode *inode, loff_t lstart)
 193 {
 194         struct address_space *mapping = &inode->i_data;
 195         const pgoff_t start = lstart >> HPAGE_SHIFT;
 196         struct pagevec pvec;
 197         pgoff_t next;
 198         int i;
 199
 200         hugetlb_truncate_reservation(HUGETLBFS_I(inode),
 201                                      lstart >> HPAGE_SHIFT);
 202         if (!mapping->nrpages)
 203                 return;
 204         pagevec_init(&pvec, 0);
 205         next = start;
 206         while (1) {
 207                 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
 208                         if (next == start)
 209                                 break;
 210                         next = start;
 211                         continue;
 212                 }
 213
 214                 for (i = 0; i < pagevec_count(&pvec); ++i) {
 215                         struct page *page = pvec.pages[i];
 216
 217                         lock_page(page);
 218                         if (page->index > next)
 219                                 next = page->index;
 220                         ++next;
 221                         truncate_huge_page(page);
 222                         unlock_page(page);
 223                         hugetlb_put_quota(mapping);
 224                 }
 225                 huge_pagevec_release(&pvec);
 226         }
 227         BUG_ON(!lstart && mapping->nrpages);
 228 }
 229
 230 static void hugetlbfs_delete_inode(struct inode *inode)
 231 {
 232         truncate_hugepages(inode, 0);
 233         clear_inode(inode);
 234 }
 235
 236 static void hugetlbfs_forget_inode(struct inode *inode)
 237 {
 238         struct super_block *sb = inode->i_sb;
 239
 240         if (!hlist_unhashed(&inode->i_hash)) {
 241                 if (!(inode->i_state & (I_DIRTY|I_LOCK)))
 242                         list_move(&inode->i_list, &inode_unused);
 243                 inodes_stat.nr_unused++;
 244                 if (!sb || (sb->s_flags & MS_ACTIVE)) {
 245                         spin_unlock(&inode_lock);
 246                         return;
 247                 }
 248                 inode->i_state |= I_WILL_FREE;
 249                 spin_unlock(&inode_lock);
 250                 /*
 251                  * write_inode_now is a noop as we set BDI_CAP_NO_WRITEBACK
 252                  * in our backing_dev_info.
 253                  */
 254                 write_inode_now(inode, 1);
 255                 spin_lock(&inode_lock);
 256                 inode->i_state &= ~I_WILL_FREE;
 257                 inodes_stat.nr_unused--;
 258                 hlist_del_init(&inode->i_hash);
 259         }
 260         list_del_init(&inode->i_list);
 261         list_del_init(&inode->i_sb_list);
 262         inode->i_state |= I_FREEING;
 263         inodes_stat.nr_inodes--;
 264         spin_unlock(&inode_lock);
 265         truncate_hugepages(inode, 0);
 266         clear_inode(inode);
 267         destroy_inode(inode);
 268 }
 269
 270 static void hugetlbfs_drop_inode(struct inode *inode)
 271 {
 272         if (!inode->i_nlink)
 273                 generic_delete_inode(inode);
 274         else
 275                 hugetlbfs_forget_inode(inode);
 276 }
 277
 278 /*
 279  * h_pgoff is in HPAGE_SIZE units.
 280  * vma->vm_pgoff is in PAGE_SIZE units.
 281  */
 282 static inline void
 283 hugetlb_vmtruncate_list(struct prio_tree_root *root, unsigned long h_pgoff)
 284 {
 285         struct vm_area_struct *vma;
 286         struct prio_tree_iter iter;
 287
 288         vma_prio_tree_foreach(vma, &iter, root, h_pgoff, ULONG_MAX) {
 289                 unsigned long h_vm_pgoff;
 290                 unsigned long v_offset;
 291
 292                 h_vm_pgoff = vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT);
 293                 v_offset = (h_pgoff - h_vm_pgoff) << HPAGE_SHIFT;
 294                 /*
 295                  * Is this VMA fully outside the truncation point?
 296                  */
 297                 if (h_vm_pgoff >= h_pgoff)
 298                         v_offset = 0;
 299
 300                 unmap_hugepage_range(vma,
 301                                 vma->vm_start + v_offset, vma->vm_end);
 302         }
 303 }
 304
 305 /*
 306  * Expanding truncates are not allowed.
 307  */
 308 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
 309 {
 310         unsigned long pgoff;
 311         struct address_space *mapping = inode->i_mapping;
 312
 313         if (offset > inode->i_size)
 314                 return -EINVAL;
 315
 316         BUG_ON(offset & ~HPAGE_MASK);
 317         pgoff = offset >> HPAGE_SHIFT;
 318
 319         inode->i_size = offset;
 320         spin_lock(&mapping->i_mmap_lock);
 321         if (!prio_tree_empty(&mapping->i_mmap))
 322                 hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff);
 323         spin_unlock(&mapping->i_mmap_lock);
 324         truncate_hugepages(inode, offset);
 325         return 0;
 326 }
 327
 328 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
 329 {
 330         struct inode *inode = dentry->d_inode;
 331         int error;
 332         unsigned int ia_valid = attr->ia_valid;
 333
 334         BUG_ON(!inode);
 335
 336         error = inode_change_ok(inode, attr);
 337         if (error)
 338                 goto out;
 339
 340         if (ia_valid & ATTR_SIZE) {
 341                 error = -EINVAL;
 342                 if (!(attr->ia_size & ~HPAGE_MASK))
 343                         error = hugetlb_vmtruncate(inode, attr->ia_size);
 344                 if (error)
 345                         goto out;
 346                 attr->ia_valid &= ~ATTR_SIZE;
 347         }
 348         error = inode_setattr(inode, attr);
 349 out:
 350         return error;
 351 }
 352
 353 static struct inode *hugetlbfs_get_inode(struct super_block *sb, uid_t uid,
 354                                         gid_t gid, int mode, dev_t dev)
 355 {
 356         struct inode *inode;
 357
 358         inode = new_inode(sb);
 359         if (inode) {
 360                 struct hugetlbfs_inode_info *info;
 361                 inode->i_mode = mode;
 362                 inode->i_uid = uid;
 363                 inode->i_gid = gid;
 364                 inode->i_blksize = HPAGE_SIZE;
 365                 inode->i_blocks = 0;
 366                 inode->i_mapping->a_ops = &hugetlbfs_aops;
 367                 inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info;
 368                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 369                 info = HUGETLBFS_I(inode);
 370                 mpol_shared_policy_init(&info->policy, MPOL_DEFAULT, NULL);
 371                 switch (mode & S_IFMT) {
 372                 default:
 373                         init_special_inode(inode, mode, dev);
 374                         break;
 375                 case S_IFREG:
 376                         inode->i_op = &hugetlbfs_inode_operations;
 377                         inode->i_fop = &hugetlbfs_file_operations;
 378                         break;
 379                 case S_IFDIR:
 380                         inode->i_op = &hugetlbfs_dir_inode_operations;
 381                         inode->i_fop = &simple_dir_operations;
 382
 383                         /* directory inodes start off with i_nlink == 2 (for "." entry) */
 384                         inode->i_nlink++;
 385                         break;
 386                 case S_IFLNK:
 387                         inode->i_op = &page_symlink_inode_operations;
 388                         break;
 389                 }
 390         }
 391         return inode;
 392 }
 393
 394 /*
 395  * File creation. Allocate an inode, and we're done..
 396  */
 397 static int hugetlbfs_mknod(struct inode *dir,
 398                         struct dentry *dentry, int mode, dev_t dev)
 399 {
 400         struct inode *inode;
 401         int error = -ENOSPC;
 402         gid_t gid;
 403
 404         if (dir->i_mode & S_ISGID) {
 405                 gid = dir->i_gid;
 406                 if (S_ISDIR(mode))
 407                         mode |= S_ISGID;
 408         } else {
 409                 gid = current->fsgid;
 410         }
 411         inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid, gid, mode, dev);
 412         if (inode) {
 413                 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 414                 d_instantiate(dentry, inode);
 415                 dget(dentry);   /* Extra count - pin the dentry in core */
 416                 error = 0;
 417         }
 418         return error;
 419 }
 420
 421 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 422 {
 423         int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
 424         if (!retval)
 425                 dir->i_nlink++;
 426         return retval;
 427 }
 428
 429 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, int mode, struct nameidata *nd)
 430 {
 431         return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
 432 }
 433
 434 static int hugetlbfs_symlink(struct inode *dir,
 435                         struct dentry *dentry, const char *symname)
 436 {
 437         struct inode *inode;
 438         int error = -ENOSPC;
 439         gid_t gid;
 440
 441         if (dir->i_mode & S_ISGID)
 442                 gid = dir->i_gid;
 443         else
 444                 gid = current->fsgid;
 445
 446         inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid,
 447                                         gid, S_IFLNK|S_IRWXUGO, 0);
 448         if (inode) {
 449                 int l = strlen(symname)+1;
 450                 error = page_symlink(inode, symname, l);
 451                 if (!error) {
 452                         d_instantiate(dentry, inode);
 453                         dget(dentry);
 454                 } else
 455                         iput(inode);
 456         }
 457         dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 458
 459         return error;
 460 }
 461
 462 /*
 463  * For direct-IO reads into hugetlb pages
 464  */
 465 static int hugetlbfs_set_page_dirty(struct page *page)
 466 {
 467         return 0;
 468 }
 469
 470 static int hugetlbfs_statfs(struct super_block *sb, struct kstatfs *buf)
 471 {
 472         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
 473
 474         buf->f_type = HUGETLBFS_MAGIC;
 475         buf->f_bsize = HPAGE_SIZE;
 476         if (sbinfo) {
 477                 spin_lock(&sbinfo->stat_lock);
 478                 /* If no limits set, just report 0 for max/free/used
 479                  * blocks, like simple_statfs() */
 480                 if (sbinfo->max_blocks >= 0) {
 481                         buf->f_blocks = sbinfo->max_blocks;
 482                         buf->f_bavail = buf->f_bfree = sbinfo->free_blocks;
 483                         buf->f_files = sbinfo->max_inodes;
 484                         buf->f_ffree = sbinfo->free_inodes;
 485                 }
 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 inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
 503 {
 504         if (sbinfo->free_inodes >= 0) {
 505                 spin_lock(&sbinfo->stat_lock);
 506                 if (unlikely(!sbinfo->free_inodes)) {
 507                         spin_unlock(&sbinfo->stat_lock);
 508                         return 0;
 509                 }
 510                 sbinfo->free_inodes--;
 511                 spin_unlock(&sbinfo->stat_lock);
 512         }
 513
 514         return 1;
 515 }
 516
 517 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
 518 {
 519         if (sbinfo->free_inodes >= 0) {
 520                 spin_lock(&sbinfo->stat_lock);
 521                 sbinfo->free_inodes++;
 522                 spin_unlock(&sbinfo->stat_lock);
 523         }
 524 }
 525
 526
 527 static kmem_cache_t *hugetlbfs_inode_cachep;
 528
 529 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
 530 {
 531         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
 532         struct hugetlbfs_inode_info *p;
 533
 534         if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
 535                 return NULL;
 536         p = kmem_cache_alloc(hugetlbfs_inode_cachep, SLAB_KERNEL);
 537         if (unlikely(!p)) {
 538                 hugetlbfs_inc_free_inodes(sbinfo);
 539                 return NULL;
 540         }
 541         p->prereserved_hpages = 0;
 542         return &p->vfs_inode;
 543 }
 544
 545 static void hugetlbfs_destroy_inode(struct inode *inode)
 546 {
 547         hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
 548         mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
 549         kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
 550 }
 551
 552 static struct address_space_operations hugetlbfs_aops = {
 553         .readpage       = hugetlbfs_readpage,
 554         .prepare_write  = hugetlbfs_prepare_write,
 555         .commit_write   = hugetlbfs_commit_write,
 556         .set_page_dirty = hugetlbfs_set_page_dirty,
 557 };
 558
 559
 560 static void init_once(void *foo, kmem_cache_t *cachep, unsigned long flags)
 561 {
 562         struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
 563
 564         if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
 565             SLAB_CTOR_CONSTRUCTOR)
 566                 inode_init_once(&ei->vfs_inode);
 567 }
 568
 569 const struct file_operations hugetlbfs_file_operations = {
 570         .mmap                   = hugetlbfs_file_mmap,
 571         .fsync                  = simple_sync_file,
 572         .get_unmapped_area      = hugetlb_get_unmapped_area,
 573 };
 574
 575 static struct inode_operations hugetlbfs_dir_inode_operations = {
 576         .create         = hugetlbfs_create,
 577         .lookup         = simple_lookup,
 578         .link           = simple_link,
 579         .unlink         = simple_unlink,
 580         .symlink        = hugetlbfs_symlink,
 581         .mkdir          = hugetlbfs_mkdir,
 582         .rmdir          = simple_rmdir,
 583         .mknod          = hugetlbfs_mknod,
 584         .rename         = simple_rename,
 585         .setattr        = hugetlbfs_setattr,
 586 };
 587
 588 static struct inode_operations hugetlbfs_inode_operations = {
 589         .setattr        = hugetlbfs_setattr,
 590 };
 591
 592 static struct super_operations hugetlbfs_ops = {
 593         .alloc_inode    = hugetlbfs_alloc_inode,
 594         .destroy_inode  = hugetlbfs_destroy_inode,
 595         .statfs         = hugetlbfs_statfs,
 596         .delete_inode   = hugetlbfs_delete_inode,
 597         .drop_inode     = hugetlbfs_drop_inode,
 598         .put_super      = hugetlbfs_put_super,
 599 };
 600
 601 static int
 602 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
 603 {
 604         char *opt, *value, *rest;
 605
 606         if (!options)
 607                 return 0;
 608         while ((opt = strsep(&options, ",")) != NULL) {
 609                 if (!*opt)
 610                         continue;
 611
 612                 value = strchr(opt, '=');
 613                 if (!value || !*value)
 614                         return -EINVAL;
 615                 else
 616                         *value++ = '\0';
 617
 618                 if (!strcmp(opt, "uid"))
 619                         pconfig->uid = simple_strtoul(value, &value, 0);
 620                 else if (!strcmp(opt, "gid"))
 621                         pconfig->gid = simple_strtoul(value, &value, 0);
 622                 else if (!strcmp(opt, "mode"))
 623                         pconfig->mode = simple_strtoul(value,&value,0) & 0777U;
 624                 else if (!strcmp(opt, "size")) {
 625                         unsigned long long size = memparse(value, &rest);
 626                         if (*rest == '%') {
 627                                 size <<= HPAGE_SHIFT;
 628                                 size *= max_huge_pages;
 629                                 do_div(size, 100);
 630                                 rest++;
 631                         }
 632                         size &= HPAGE_MASK;
 633                         pconfig->nr_blocks = (size >> HPAGE_SHIFT);
 634                         value = rest;
 635                 } else if (!strcmp(opt,"nr_inodes")) {
 636                         pconfig->nr_inodes = memparse(value, &rest);
 637                         value = rest;
 638                 } else
 639                         return -EINVAL;
 640
 641                 if (*value)
 642                         return -EINVAL;
 643         }
 644         return 0;
 645 }
 646
 647 static int
 648 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
 649 {
 650         struct inode * inode;
 651         struct dentry * root;
 652         int ret;
 653         struct hugetlbfs_config config;
 654         struct hugetlbfs_sb_info *sbinfo;
 655
 656         config.nr_blocks = -1; /* No limit on size by default */
 657         config.nr_inodes = -1; /* No limit on number of inodes by default */
 658         config.uid = current->fsuid;
 659         config.gid = current->fsgid;
 660         config.mode = 0755;
 661         ret = hugetlbfs_parse_options(data, &config);
 662
 663         if (ret)
 664                 return ret;
 665
 666         sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
 667         if (!sbinfo)
 668                 return -ENOMEM;
 669         sb->s_fs_info = sbinfo;
 670         spin_lock_init(&sbinfo->stat_lock);
 671         sbinfo->max_blocks = config.nr_blocks;
 672         sbinfo->free_blocks = config.nr_blocks;
 673         sbinfo->max_inodes = config.nr_inodes;
 674         sbinfo->free_inodes = config.nr_inodes;
 675         sb->s_maxbytes = MAX_LFS_FILESIZE;
 676         sb->s_blocksize = HPAGE_SIZE;
 677         sb->s_blocksize_bits = HPAGE_SHIFT;
 678         sb->s_magic = HUGETLBFS_MAGIC;
 679         sb->s_op = &hugetlbfs_ops;
 680         sb->s_time_gran = 1;
 681         inode = hugetlbfs_get_inode(sb, config.uid, config.gid,
 682                                         S_IFDIR | config.mode, 0);
 683         if (!inode)
 684                 goto out_free;
 685
 686         root = d_alloc_root(inode);
 687         if (!root) {
 688                 iput(inode);
 689                 goto out_free;
 690         }
 691         sb->s_root = root;
 692         return 0;
 693 out_free:
 694         kfree(sbinfo);
 695         return -ENOMEM;
 696 }
 697
 698 int hugetlb_get_quota(struct address_space *mapping)
 699 {
 700         int ret = 0;
 701         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
 702
 703         if (sbinfo->free_blocks > -1) {
 704                 spin_lock(&sbinfo->stat_lock);
 705                 if (sbinfo->free_blocks > 0)
 706                         sbinfo->free_blocks--;
 707                 else
 708                         ret = -ENOMEM;
 709                 spin_unlock(&sbinfo->stat_lock);
 710         }
 711
 712         return ret;
 713 }
 714
 715 void hugetlb_put_quota(struct address_space *mapping)
 716 {
 717         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
 718
 719         if (sbinfo->free_blocks > -1) {
 720                 spin_lock(&sbinfo->stat_lock);
 721                 sbinfo->free_blocks++;
 722                 spin_unlock(&sbinfo->stat_lock);
 723         }
 724 }
 725
 726 static struct super_block *hugetlbfs_get_sb(struct file_system_type *fs_type,
 727         int flags, const char *dev_name, void *data)
 728 {
 729         return get_sb_nodev(fs_type, flags, data, hugetlbfs_fill_super);
 730 }
 731
 732 static struct file_system_type hugetlbfs_fs_type = {
 733         .name           = "hugetlbfs",
 734         .get_sb         = hugetlbfs_get_sb,
 735         .kill_sb        = kill_litter_super,
 736 };
 737
 738 static struct vfsmount *hugetlbfs_vfsmount;
 739
 740 static int can_do_hugetlb_shm(void)
 741 {
 742         return likely(capable(CAP_IPC_LOCK) ||
 743                         in_group_p(sysctl_hugetlb_shm_group) ||
 744                         can_do_mlock());
 745 }
 746
 747 struct file *hugetlb_zero_setup(size_t size)
 748 {
 749         int error = -ENOMEM;
 750         struct file *file;
 751         struct inode *inode;
 752         struct dentry *dentry, *root;
 753         struct qstr quick_string;
 754         char buf[16];
 755         static atomic_t counter;
 756
 757         if (!can_do_hugetlb_shm())
 758                 return ERR_PTR(-EPERM);
 759
 760         if (!user_shm_lock(size, current->user))
 761                 return ERR_PTR(-ENOMEM);
 762
 763         root = hugetlbfs_vfsmount->mnt_root;
 764         snprintf(buf, 16, "%u", atomic_inc_return(&counter));
 765         quick_string.name = buf;
 766         quick_string.len = strlen(quick_string.name);
 767         quick_string.hash = 0;
 768         dentry = d_alloc(root, &quick_string);
 769         if (!dentry)
 770                 goto out_shm_unlock;
 771
 772         error = -ENFILE;
 773         file = get_empty_filp();
 774         if (!file)
 775                 goto out_dentry;
 776
 777         error = -ENOSPC;
 778         inode = hugetlbfs_get_inode(root->d_sb, current->fsuid,
 779                                 current->fsgid, S_IFREG | S_IRWXUGO, 0);
 780         if (!inode)
 781                 goto out_file;
 782
 783         error = -ENOMEM;
 784         if (hugetlb_extend_reservation(HUGETLBFS_I(inode),
 785                                        size >> HPAGE_SHIFT) != 0)
 786                 goto out_inode;
 787
 788         d_instantiate(dentry, inode);
 789         inode->i_size = size;
 790         inode->i_nlink = 0;
 791         file->f_vfsmnt = mntget(hugetlbfs_vfsmount);
 792         file->f_dentry = dentry;
 793         file->f_mapping = inode->i_mapping;
 794         file->f_op = &hugetlbfs_file_operations;
 795         file->f_mode = FMODE_WRITE | FMODE_READ;
 796         return file;
 797
 798 out_inode:
 799         iput(inode);
 800 out_file:
 801         put_filp(file);
 802 out_dentry:
 803         dput(dentry);
 804 out_shm_unlock:
 805         user_shm_unlock(size, current->user);
 806         return ERR_PTR(error);
 807 }
 808
 809 static int __init init_hugetlbfs_fs(void)
 810 {
 811         int error;
 812         struct vfsmount *vfsmount;
 813
 814         hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
 815                                         sizeof(struct hugetlbfs_inode_info),
 816                                         0, 0, init_once, NULL);
 817         if (hugetlbfs_inode_cachep == NULL)
 818                 return -ENOMEM;
 819
 820         error = register_filesystem(&hugetlbfs_fs_type);
 821         if (error)
 822                 goto out;
 823
 824         vfsmount = kern_mount(&hugetlbfs_fs_type);
 825
 826         if (!IS_ERR(vfsmount)) {
 827                 hugetlbfs_vfsmount = vfsmount;
 828                 return 0;
 829         }
 830
 831         error = PTR_ERR(vfsmount);
 832
 833  out:
 834         if (error)
 835                 kmem_cache_destroy(hugetlbfs_inode_cachep);
 836         return error;
 837 }
 838
 839 static void __exit exit_hugetlbfs_fs(void)
 840 {
 841         kmem_cache_destroy(hugetlbfs_inode_cachep);
 842         unregister_filesystem(&hugetlbfs_fs_type);
 843 }
 844
 845 module_init(init_hugetlbfs_fs)
 846 module_exit(exit_hugetlbfs_fs)
 847
 848 MODULE_LICENSE("GPL");