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 const 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         loff_t len, vma_len;
  63         int ret;
  64
  65         if (vma->vm_pgoff & (HPAGE_SIZE / PAGE_SIZE - 1))
  66                 return -EINVAL;
  67
  68         if (vma->vm_start & ~HPAGE_MASK)
  69                 return -EINVAL;
  70
  71         if (vma->vm_end & ~HPAGE_MASK)
  72                 return -EINVAL;
  73
  74         if (vma->vm_end - vma->vm_start < HPAGE_SIZE)
  75                 return -EINVAL;
  76
  77         vma_len = (loff_t)(vma->vm_end - vma->vm_start);
  78
  79         mutex_lock(&inode->i_mutex);
  80         file_accessed(file);
  81         vma->vm_flags |= VM_HUGETLB | VM_RESERVED;
  82         vma->vm_ops = &hugetlb_vm_ops;
  83
  84         ret = -ENOMEM;
  85         len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
  86
  87         if (vma->vm_flags & VM_MAYSHARE &&
  88             hugetlb_reserve_pages(inode, vma->vm_pgoff >> (HPAGE_SHIFT-PAGE_SHIFT),
  89                                   len >> HPAGE_SHIFT))
  90                 goto out;
  91
  92         ret = 0;
  93         hugetlb_prefault_arch_hook(vma->vm_mm);
  94         if (vma->vm_flags & VM_WRITE && inode->i_size < len)
  95                 inode->i_size = len;
  96 out:
  97         mutex_unlock(&inode->i_mutex);
  98
  99         return ret;
 100 }
 101
 102 /*
 103  * Called under down_write(mmap_sem).
 104  */
 105
 106 #ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
 107 unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 108                 unsigned long len, unsigned long pgoff, unsigned long flags);
 109 #else
 110 static unsigned long
 111 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 112                 unsigned long len, unsigned long pgoff, unsigned long flags)
 113 {
 114         struct mm_struct *mm = current->mm;
 115         struct vm_area_struct *vma;
 116         unsigned long start_addr;
 117
 118         if (len & ~HPAGE_MASK)
 119                 return -EINVAL;
 120         if (len > TASK_SIZE)
 121                 return -ENOMEM;
 122
 123         if (addr) {
 124                 addr = ALIGN(addr, HPAGE_SIZE);
 125                 vma = find_vma(mm, addr);
 126                 if (TASK_SIZE - len >= addr &&
 127                     (!vma || addr + len <= vma->vm_start))
 128                         return addr;
 129         }
 130
 131         start_addr = mm->free_area_cache;
 132
 133         if (len <= mm->cached_hole_size)
 134                 start_addr = TASK_UNMAPPED_BASE;
 135
 136 full_search:
 137         addr = ALIGN(start_addr, HPAGE_SIZE);
 138
 139         for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
 140                 /* At this point:  (!vma || addr < vma->vm_end). */
 141                 if (TASK_SIZE - len < addr) {
 142                         /*
 143                          * Start a new search - just in case we missed
 144                          * some holes.
 145                          */
 146                         if (start_addr != TASK_UNMAPPED_BASE) {
 147                                 start_addr = TASK_UNMAPPED_BASE;
 148                                 goto full_search;
 149                         }
 150                         return -ENOMEM;
 151                 }
 152
 153                 if (!vma || addr + len <= vma->vm_start)
 154                         return addr;
 155                 addr = ALIGN(vma->vm_end, HPAGE_SIZE);
 156         }
 157 }
 158 #endif
 159
 160 /*
 161  * Read a page. Again trivial. If it didn't already exist
 162  * in the page cache, it is zero-filled.
 163  */
 164 static int hugetlbfs_readpage(struct file *file, struct page * page)
 165 {
 166         unlock_page(page);
 167         return -EINVAL;
 168 }
 169
 170 static int hugetlbfs_prepare_write(struct file *file,
 171                         struct page *page, unsigned offset, unsigned to)
 172 {
 173         return -EINVAL;
 174 }
 175
 176 static int hugetlbfs_commit_write(struct file *file,
 177                         struct page *page, unsigned offset, unsigned to)
 178 {
 179         return -EINVAL;
 180 }
 181
 182 static void truncate_huge_page(struct page *page)
 183 {
 184         clear_page_dirty(page);
 185         ClearPageUptodate(page);
 186         remove_from_page_cache(page);
 187         put_page(page);
 188 }
 189
 190 static void truncate_hugepages(struct inode *inode, loff_t lstart)
 191 {
 192         struct address_space *mapping = &inode->i_data;
 193         const pgoff_t start = lstart >> HPAGE_SHIFT;
 194         struct pagevec pvec;
 195         pgoff_t next;
 196         int i, freed = 0;
 197
 198         pagevec_init(&pvec, 0);
 199         next = start;
 200         while (1) {
 201                 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
 202                         if (next == start)
 203                                 break;
 204                         next = start;
 205                         continue;
 206                 }
 207
 208                 for (i = 0; i < pagevec_count(&pvec); ++i) {
 209                         struct page *page = pvec.pages[i];
 210
 211                         lock_page(page);
 212                         if (page->index > next)
 213                                 next = page->index;
 214                         ++next;
 215                         truncate_huge_page(page);
 216                         unlock_page(page);
 217                         hugetlb_put_quota(mapping);
 218                         freed++;
 219                 }
 220                 huge_pagevec_release(&pvec);
 221         }
 222         BUG_ON(!lstart && mapping->nrpages);
 223         hugetlb_unreserve_pages(inode, start, freed);
 224 }
 225
 226 static void hugetlbfs_delete_inode(struct inode *inode)
 227 {
 228         truncate_hugepages(inode, 0);
 229         clear_inode(inode);
 230 }
 231
 232 static void hugetlbfs_forget_inode(struct inode *inode) __releases(inode_lock)
 233 {
 234         struct super_block *sb = inode->i_sb;
 235
 236         if (!hlist_unhashed(&inode->i_hash)) {
 237                 if (!(inode->i_state & (I_DIRTY|I_LOCK)))
 238                         list_move(&inode->i_list, &inode_unused);
 239                 inodes_stat.nr_unused++;
 240                 if (!sb || (sb->s_flags & MS_ACTIVE)) {
 241                         spin_unlock(&inode_lock);
 242                         return;
 243                 }
 244                 inode->i_state |= I_WILL_FREE;
 245                 spin_unlock(&inode_lock);
 246                 /*
 247                  * write_inode_now is a noop as we set BDI_CAP_NO_WRITEBACK
 248                  * in our backing_dev_info.
 249                  */
 250                 write_inode_now(inode, 1);
 251                 spin_lock(&inode_lock);
 252                 inode->i_state &= ~I_WILL_FREE;
 253                 inodes_stat.nr_unused--;
 254                 hlist_del_init(&inode->i_hash);
 255         }
 256         list_del_init(&inode->i_list);
 257         list_del_init(&inode->i_sb_list);
 258         inode->i_state |= I_FREEING;
 259         inodes_stat.nr_inodes--;
 260         spin_unlock(&inode_lock);
 261         truncate_hugepages(inode, 0);
 262         clear_inode(inode);
 263         destroy_inode(inode);
 264 }
 265
 266 static void hugetlbfs_drop_inode(struct inode *inode)
 267 {
 268         if (!inode->i_nlink)
 269                 generic_delete_inode(inode);
 270         else
 271                 hugetlbfs_forget_inode(inode);
 272 }
 273
 274 static inline void
 275 hugetlb_vmtruncate_list(struct prio_tree_root *root, pgoff_t pgoff)
 276 {
 277         struct vm_area_struct *vma;
 278         struct prio_tree_iter iter;
 279
 280         vma_prio_tree_foreach(vma, &iter, root, pgoff, ULONG_MAX) {
 281                 unsigned long v_offset;
 282
 283                 /*
 284                  * Can the expression below overflow on 32-bit arches?
 285                  * No, because the prio_tree returns us only those vmas
 286                  * which overlap the truncated area starting at pgoff,
 287                  * and no vma on a 32-bit arch can span beyond the 4GB.
 288                  */
 289                 if (vma->vm_pgoff < pgoff)
 290                         v_offset = (pgoff - vma->vm_pgoff) << PAGE_SHIFT;
 291                 else
 292                         v_offset = 0;
 293
 294                 __unmap_hugepage_range(vma,
 295                                 vma->vm_start + v_offset, vma->vm_end);
 296         }
 297 }
 298
 299 /*
 300  * Expanding truncates are not allowed.
 301  */
 302 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
 303 {
 304         pgoff_t pgoff;
 305         struct address_space *mapping = inode->i_mapping;
 306
 307         if (offset > inode->i_size)
 308                 return -EINVAL;
 309
 310         BUG_ON(offset & ~HPAGE_MASK);
 311         pgoff = offset >> PAGE_SHIFT;
 312
 313         inode->i_size = offset;
 314         spin_lock(&mapping->i_mmap_lock);
 315         if (!prio_tree_empty(&mapping->i_mmap))
 316                 hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff);
 317         spin_unlock(&mapping->i_mmap_lock);
 318         truncate_hugepages(inode, offset);
 319         return 0;
 320 }
 321
 322 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
 323 {
 324         struct inode *inode = dentry->d_inode;
 325         int error;
 326         unsigned int ia_valid = attr->ia_valid;
 327
 328         BUG_ON(!inode);
 329
 330         error = inode_change_ok(inode, attr);
 331         if (error)
 332                 goto out;
 333
 334         if (ia_valid & ATTR_SIZE) {
 335                 error = -EINVAL;
 336                 if (!(attr->ia_size & ~HPAGE_MASK))
 337                         error = hugetlb_vmtruncate(inode, attr->ia_size);
 338                 if (error)
 339                         goto out;
 340                 attr->ia_valid &= ~ATTR_SIZE;
 341         }
 342         error = inode_setattr(inode, attr);
 343 out:
 344         return error;
 345 }
 346
 347 static struct inode *hugetlbfs_get_inode(struct super_block *sb, uid_t uid,
 348                                         gid_t gid, int mode, dev_t dev)
 349 {
 350         struct inode *inode;
 351
 352         inode = new_inode(sb);
 353         if (inode) {
 354                 struct hugetlbfs_inode_info *info;
 355                 inode->i_mode = mode;
 356                 inode->i_uid = uid;
 357                 inode->i_gid = gid;
 358                 inode->i_blocks = 0;
 359                 inode->i_mapping->a_ops = &hugetlbfs_aops;
 360                 inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info;
 361                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 362                 INIT_LIST_HEAD(&inode->i_mapping->private_list);
 363                 info = HUGETLBFS_I(inode);
 364                 mpol_shared_policy_init(&info->policy, MPOL_DEFAULT, NULL);
 365                 switch (mode & S_IFMT) {
 366                 default:
 367                         init_special_inode(inode, mode, dev);
 368                         break;
 369                 case S_IFREG:
 370                         inode->i_op = &hugetlbfs_inode_operations;
 371                         inode->i_fop = &hugetlbfs_file_operations;
 372                         break;
 373                 case S_IFDIR:
 374                         inode->i_op = &hugetlbfs_dir_inode_operations;
 375                         inode->i_fop = &simple_dir_operations;
 376
 377                         /* directory inodes start off with i_nlink == 2 (for "." entry) */
 378                         inc_nlink(inode);
 379                         break;
 380                 case S_IFLNK:
 381                         inode->i_op = &page_symlink_inode_operations;
 382                         break;
 383                 }
 384         }
 385         return inode;
 386 }
 387
 388 /*
 389  * File creation. Allocate an inode, and we're done..
 390  */
 391 static int hugetlbfs_mknod(struct inode *dir,
 392                         struct dentry *dentry, int mode, dev_t dev)
 393 {
 394         struct inode *inode;
 395         int error = -ENOSPC;
 396         gid_t gid;
 397
 398         if (dir->i_mode & S_ISGID) {
 399                 gid = dir->i_gid;
 400                 if (S_ISDIR(mode))
 401                         mode |= S_ISGID;
 402         } else {
 403                 gid = current->fsgid;
 404         }
 405         inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid, gid, mode, dev);
 406         if (inode) {
 407                 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 408                 d_instantiate(dentry, inode);
 409                 dget(dentry);   /* Extra count - pin the dentry in core */
 410                 error = 0;
 411         }
 412         return error;
 413 }
 414
 415 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 416 {
 417         int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
 418         if (!retval)
 419                 inc_nlink(dir);
 420         return retval;
 421 }
 422
 423 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, int mode, struct nameidata *nd)
 424 {
 425         return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
 426 }
 427
 428 static int hugetlbfs_symlink(struct inode *dir,
 429                         struct dentry *dentry, const char *symname)
 430 {
 431         struct inode *inode;
 432         int error = -ENOSPC;
 433         gid_t gid;
 434
 435         if (dir->i_mode & S_ISGID)
 436                 gid = dir->i_gid;
 437         else
 438                 gid = current->fsgid;
 439
 440         inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid,
 441                                         gid, S_IFLNK|S_IRWXUGO, 0);
 442         if (inode) {
 443                 int l = strlen(symname)+1;
 444                 error = page_symlink(inode, symname, l);
 445                 if (!error) {
 446                         d_instantiate(dentry, inode);
 447                         dget(dentry);
 448                 } else
 449                         iput(inode);
 450         }
 451         dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 452
 453         return error;
 454 }
 455
 456 /*
 457  * For direct-IO reads into hugetlb pages
 458  */
 459 static int hugetlbfs_set_page_dirty(struct page *page)
 460 {
 461         return 0;
 462 }
 463
 464 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 465 {
 466         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
 467
 468         buf->f_type = HUGETLBFS_MAGIC;
 469         buf->f_bsize = HPAGE_SIZE;
 470         if (sbinfo) {
 471                 spin_lock(&sbinfo->stat_lock);
 472                 /* If no limits set, just report 0 for max/free/used
 473                  * blocks, like simple_statfs() */
 474                 if (sbinfo->max_blocks >= 0) {
 475                         buf->f_blocks = sbinfo->max_blocks;
 476                         buf->f_bavail = buf->f_bfree = sbinfo->free_blocks;
 477                         buf->f_files = sbinfo->max_inodes;
 478                         buf->f_ffree = sbinfo->free_inodes;
 479                 }
 480                 spin_unlock(&sbinfo->stat_lock);
 481         }
 482         buf->f_namelen = NAME_MAX;
 483         return 0;
 484 }
 485
 486 static void hugetlbfs_put_super(struct super_block *sb)
 487 {
 488         struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
 489
 490         if (sbi) {
 491                 sb->s_fs_info = NULL;
 492                 kfree(sbi);
 493         }
 494 }
 495
 496 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
 497 {
 498         if (sbinfo->free_inodes >= 0) {
 499                 spin_lock(&sbinfo->stat_lock);
 500                 if (unlikely(!sbinfo->free_inodes)) {
 501                         spin_unlock(&sbinfo->stat_lock);
 502                         return 0;
 503                 }
 504                 sbinfo->free_inodes--;
 505                 spin_unlock(&sbinfo->stat_lock);
 506         }
 507
 508         return 1;
 509 }
 510
 511 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
 512 {
 513         if (sbinfo->free_inodes >= 0) {
 514                 spin_lock(&sbinfo->stat_lock);
 515                 sbinfo->free_inodes++;
 516                 spin_unlock(&sbinfo->stat_lock);
 517         }
 518 }
 519
 520
 521 static kmem_cache_t *hugetlbfs_inode_cachep;
 522
 523 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
 524 {
 525         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
 526         struct hugetlbfs_inode_info *p;
 527
 528         if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
 529                 return NULL;
 530         p = kmem_cache_alloc(hugetlbfs_inode_cachep, SLAB_KERNEL);
 531         if (unlikely(!p)) {
 532                 hugetlbfs_inc_free_inodes(sbinfo);
 533                 return NULL;
 534         }
 535         return &p->vfs_inode;
 536 }
 537
 538 static void hugetlbfs_destroy_inode(struct inode *inode)
 539 {
 540         hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
 541         mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
 542         kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
 543 }
 544
 545 static const struct address_space_operations hugetlbfs_aops = {
 546         .readpage       = hugetlbfs_readpage,
 547         .prepare_write  = hugetlbfs_prepare_write,
 548         .commit_write   = hugetlbfs_commit_write,
 549         .set_page_dirty = hugetlbfs_set_page_dirty,
 550 };
 551
 552
 553 static void init_once(void *foo, kmem_cache_t *cachep, unsigned long flags)
 554 {
 555         struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
 556
 557         if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
 558             SLAB_CTOR_CONSTRUCTOR)
 559                 inode_init_once(&ei->vfs_inode);
 560 }
 561
 562 const struct file_operations hugetlbfs_file_operations = {
 563         .mmap                   = hugetlbfs_file_mmap,
 564         .fsync                  = simple_sync_file,
 565         .get_unmapped_area      = hugetlb_get_unmapped_area,
 566 };
 567
 568 static struct inode_operations hugetlbfs_dir_inode_operations = {
 569         .create         = hugetlbfs_create,
 570         .lookup         = simple_lookup,
 571         .link           = simple_link,
 572         .unlink         = simple_unlink,
 573         .symlink        = hugetlbfs_symlink,
 574         .mkdir          = hugetlbfs_mkdir,
 575         .rmdir          = simple_rmdir,
 576         .mknod          = hugetlbfs_mknod,
 577         .rename         = simple_rename,
 578         .setattr        = hugetlbfs_setattr,
 579 };
 580
 581 static struct inode_operations hugetlbfs_inode_operations = {
 582         .setattr        = hugetlbfs_setattr,
 583 };
 584
 585 static struct super_operations hugetlbfs_ops = {
 586         .alloc_inode    = hugetlbfs_alloc_inode,
 587         .destroy_inode  = hugetlbfs_destroy_inode,
 588         .statfs         = hugetlbfs_statfs,
 589         .delete_inode   = hugetlbfs_delete_inode,
 590         .drop_inode     = hugetlbfs_drop_inode,
 591         .put_super      = hugetlbfs_put_super,
 592 };
 593
 594 static int
 595 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
 596 {
 597         char *opt, *value, *rest;
 598
 599         if (!options)
 600                 return 0;
 601         while ((opt = strsep(&options, ",")) != NULL) {
 602                 if (!*opt)
 603                         continue;
 604
 605                 value = strchr(opt, '=');
 606                 if (!value || !*value)
 607                         return -EINVAL;
 608                 else
 609                         *value++ = '\0';
 610
 611                 if (!strcmp(opt, "uid"))
 612                         pconfig->uid = simple_strtoul(value, &value, 0);
 613                 else if (!strcmp(opt, "gid"))
 614                         pconfig->gid = simple_strtoul(value, &value, 0);
 615                 else if (!strcmp(opt, "mode"))
 616                         pconfig->mode = simple_strtoul(value,&value,0) & 0777U;
 617                 else if (!strcmp(opt, "size")) {
 618                         unsigned long long size = memparse(value, &rest);
 619                         if (*rest == '%') {
 620                                 size <<= HPAGE_SHIFT;
 621                                 size *= max_huge_pages;
 622                                 do_div(size, 100);
 623                                 rest++;
 624                         }
 625                         pconfig->nr_blocks = (size >> HPAGE_SHIFT);
 626                         value = rest;
 627                 } else if (!strcmp(opt,"nr_inodes")) {
 628                         pconfig->nr_inodes = memparse(value, &rest);
 629                         value = rest;
 630                 } else
 631                         return -EINVAL;
 632
 633                 if (*value)
 634                         return -EINVAL;
 635         }
 636         return 0;
 637 }
 638
 639 static int
 640 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
 641 {
 642         struct inode * inode;
 643         struct dentry * root;
 644         int ret;
 645         struct hugetlbfs_config config;
 646         struct hugetlbfs_sb_info *sbinfo;
 647
 648         config.nr_blocks = -1; /* No limit on size by default */
 649         config.nr_inodes = -1; /* No limit on number of inodes by default */
 650         config.uid = current->fsuid;
 651         config.gid = current->fsgid;
 652         config.mode = 0755;
 653         ret = hugetlbfs_parse_options(data, &config);
 654
 655         if (ret)
 656                 return ret;
 657
 658         sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
 659         if (!sbinfo)
 660                 return -ENOMEM;
 661         sb->s_fs_info = sbinfo;
 662         spin_lock_init(&sbinfo->stat_lock);
 663         sbinfo->max_blocks = config.nr_blocks;
 664         sbinfo->free_blocks = config.nr_blocks;
 665         sbinfo->max_inodes = config.nr_inodes;
 666         sbinfo->free_inodes = config.nr_inodes;
 667         sb->s_maxbytes = MAX_LFS_FILESIZE;
 668         sb->s_blocksize = HPAGE_SIZE;
 669         sb->s_blocksize_bits = HPAGE_SHIFT;
 670         sb->s_magic = HUGETLBFS_MAGIC;
 671         sb->s_op = &hugetlbfs_ops;
 672         sb->s_time_gran = 1;
 673         inode = hugetlbfs_get_inode(sb, config.uid, config.gid,
 674                                         S_IFDIR | config.mode, 0);
 675         if (!inode)
 676                 goto out_free;
 677
 678         root = d_alloc_root(inode);
 679         if (!root) {
 680                 iput(inode);
 681                 goto out_free;
 682         }
 683         sb->s_root = root;
 684         return 0;
 685 out_free:
 686         kfree(sbinfo);
 687         return -ENOMEM;
 688 }
 689
 690 int hugetlb_get_quota(struct address_space *mapping)
 691 {
 692         int ret = 0;
 693         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
 694
 695         if (sbinfo->free_blocks > -1) {
 696                 spin_lock(&sbinfo->stat_lock);
 697                 if (sbinfo->free_blocks > 0)
 698                         sbinfo->free_blocks--;
 699                 else
 700                         ret = -ENOMEM;
 701                 spin_unlock(&sbinfo->stat_lock);
 702         }
 703
 704         return ret;
 705 }
 706
 707 void hugetlb_put_quota(struct address_space *mapping)
 708 {
 709         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
 710
 711         if (sbinfo->free_blocks > -1) {
 712                 spin_lock(&sbinfo->stat_lock);
 713                 sbinfo->free_blocks++;
 714                 spin_unlock(&sbinfo->stat_lock);
 715         }
 716 }
 717
 718 static int hugetlbfs_get_sb(struct file_system_type *fs_type,
 719         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
 720 {
 721         return get_sb_nodev(fs_type, flags, data, hugetlbfs_fill_super, mnt);
 722 }
 723
 724 static struct file_system_type hugetlbfs_fs_type = {
 725         .name           = "hugetlbfs",
 726         .get_sb         = hugetlbfs_get_sb,
 727         .kill_sb        = kill_litter_super,
 728 };
 729
 730 static struct vfsmount *hugetlbfs_vfsmount;
 731
 732 static int can_do_hugetlb_shm(void)
 733 {
 734         return likely(capable(CAP_IPC_LOCK) ||
 735                         in_group_p(sysctl_hugetlb_shm_group) ||
 736                         can_do_mlock());
 737 }
 738
 739 struct file *hugetlb_zero_setup(size_t size)
 740 {
 741         int error = -ENOMEM;
 742         struct file *file;
 743         struct inode *inode;
 744         struct dentry *dentry, *root;
 745         struct qstr quick_string;
 746         char buf[16];
 747         static atomic_t counter;
 748
 749         if (!can_do_hugetlb_shm())
 750                 return ERR_PTR(-EPERM);
 751
 752         if (!user_shm_lock(size, current->user))
 753                 return ERR_PTR(-ENOMEM);
 754
 755         root = hugetlbfs_vfsmount->mnt_root;
 756         snprintf(buf, 16, "%u", atomic_inc_return(&counter));
 757         quick_string.name = buf;
 758         quick_string.len = strlen(quick_string.name);
 759         quick_string.hash = 0;
 760         dentry = d_alloc(root, &quick_string);
 761         if (!dentry)
 762                 goto out_shm_unlock;
 763
 764         error = -ENFILE;
 765         file = get_empty_filp();
 766         if (!file)
 767                 goto out_dentry;
 768
 769         error = -ENOSPC;
 770         inode = hugetlbfs_get_inode(root->d_sb, current->fsuid,
 771                                 current->fsgid, S_IFREG | S_IRWXUGO, 0);
 772         if (!inode)
 773                 goto out_file;
 774
 775         error = -ENOMEM;
 776         if (hugetlb_reserve_pages(inode, 0, size >> HPAGE_SHIFT))
 777                 goto out_inode;
 778
 779         d_instantiate(dentry, inode);
 780         inode->i_size = size;
 781         inode->i_nlink = 0;
 782         file->f_vfsmnt = mntget(hugetlbfs_vfsmount);
 783         file->f_dentry = dentry;
 784         file->f_mapping = inode->i_mapping;
 785         file->f_op = &hugetlbfs_file_operations;
 786         file->f_mode = FMODE_WRITE | FMODE_READ;
 787         return file;
 788
 789 out_inode:
 790         iput(inode);
 791 out_file:
 792         put_filp(file);
 793 out_dentry:
 794         dput(dentry);
 795 out_shm_unlock:
 796         user_shm_unlock(size, current->user);
 797         return ERR_PTR(error);
 798 }
 799
 800 static int __init init_hugetlbfs_fs(void)
 801 {
 802         int error;
 803         struct vfsmount *vfsmount;
 804
 805         hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
 806                                         sizeof(struct hugetlbfs_inode_info),
 807                                         0, 0, init_once, NULL);
 808         if (hugetlbfs_inode_cachep == NULL)
 809                 return -ENOMEM;
 810
 811         error = register_filesystem(&hugetlbfs_fs_type);
 812         if (error)
 813                 goto out;
 814
 815         vfsmount = kern_mount(&hugetlbfs_fs_type);
 816
 817         if (!IS_ERR(vfsmount)) {
 818                 hugetlbfs_vfsmount = vfsmount;
 819                 return 0;
 820         }
 821
 822         error = PTR_ERR(vfsmount);
 823
 824  out:
 825         if (error)
 826                 kmem_cache_destroy(hugetlbfs_inode_cachep);
 827         return error;
 828 }
 829
 830 static void __exit exit_hugetlbfs_fs(void)
 831 {
 832         kmem_cache_destroy(hugetlbfs_inode_cachep);
 833         unregister_filesystem(&hugetlbfs_fs_type);
 834 }
 835
 836 module_init(init_hugetlbfs_fs)
 837 module_exit(exit_hugetlbfs_fs)
 838
 839 MODULE_LICENSE("GPL");