git.oblomov.eu Git - linux-2.6/blob - fs/hugetlbfs/inode.c

   1 /*
   2  * hugetlbpage-backed filesystem.  Based on ramfs.
   3  *
   4  * William Irwin, 2002
   5  *
   6  * Copyright (C) 2002 Linus Torvalds.
   7  */
   8
   9 #include <linux/module.h>
  10 #include <linux/thread_info.h>
  11 #include <asm/current.h>
  12 #include <linux/sched.h>                /* remove ASAP */
  13 #include <linux/fs.h>
  14 #include <linux/mount.h>
  15 #include <linux/file.h>
  16 #include <linux/writeback.h>
  17 #include <linux/pagemap.h>
  18 #include <linux/highmem.h>
  19 #include <linux/init.h>
  20 #include <linux/string.h>
  21 #include <linux/backing-dev.h>
  22 #include <linux/hugetlb.h>
  23 #include <linux/pagevec.h>
  24 #include <linux/quotaops.h>
  25 #include <linux/slab.h>
  26 #include <linux/dnotify.h>
  27 #include <linux/statfs.h>
  28 #include <linux/security.h>
  29
  30 #include <asm/uaccess.h>
  31
  32 /* some random number */
  33 #define HUGETLBFS_MAGIC 0x958458f6
  34
  35 static struct super_operations hugetlbfs_ops;
  36 static struct address_space_operations hugetlbfs_aops;
  37 struct file_operations hugetlbfs_file_operations;
  38 static struct inode_operations hugetlbfs_dir_inode_operations;
  39 static struct inode_operations hugetlbfs_inode_operations;
  40
  41 static struct backing_dev_info hugetlbfs_backing_dev_info = {
  42         .ra_pages       = 0,    /* No readahead */
  43         .capabilities   = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
  44 };
  45
  46 int sysctl_hugetlb_shm_group;
  47
  48 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
  49 {
  50         struct inode *inode = file->f_dentry->d_inode;
  51         struct address_space *mapping = inode->i_mapping;
  52         loff_t len, vma_len;
  53         int ret;
  54
  55         if ((vma->vm_flags & (VM_MAYSHARE | VM_WRITE)) == VM_WRITE)
  56                 return -EINVAL;
  57
  58         if (vma->vm_pgoff & (HPAGE_SIZE / PAGE_SIZE - 1))
  59                 return -EINVAL;
  60
  61         if (vma->vm_start & ~HPAGE_MASK)
  62                 return -EINVAL;
  63
  64         if (vma->vm_end & ~HPAGE_MASK)
  65                 return -EINVAL;
  66
  67         if (vma->vm_end - vma->vm_start < HPAGE_SIZE)
  68                 return -EINVAL;
  69
  70         vma_len = (loff_t)(vma->vm_end - vma->vm_start);
  71
  72         down(&inode->i_sem);
  73         file_accessed(file);
  74         vma->vm_flags |= VM_HUGETLB | VM_RESERVED;
  75         vma->vm_ops = &hugetlb_vm_ops;
  76
  77         ret = -ENOMEM;
  78         len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
  79         if (!(vma->vm_flags & VM_WRITE) && len > inode->i_size)
  80                 goto out;
  81
  82         ret = hugetlb_prefault(mapping, vma);
  83         if (ret)
  84                 goto out;
  85
  86         if (inode->i_size < len)
  87                 inode->i_size = len;
  88 out:
  89         up(&inode->i_sem);
  90
  91         return ret;
  92 }
  93
  94 /*
  95  * Called under down_write(mmap_sem), page_table_lock is not held
  96  */
  97
  98 #ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
  99 unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 100                 unsigned long len, unsigned long pgoff, unsigned long flags);
 101 #else
 102 static unsigned long
 103 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 104                 unsigned long len, unsigned long pgoff, unsigned long flags)
 105 {
 106         struct mm_struct *mm = current->mm;
 107         struct vm_area_struct *vma;
 108         unsigned long start_addr;
 109
 110         if (len & ~HPAGE_MASK)
 111                 return -EINVAL;
 112         if (len > TASK_SIZE)
 113                 return -ENOMEM;
 114
 115         if (addr) {
 116                 addr = ALIGN(addr, HPAGE_SIZE);
 117                 vma = find_vma(mm, addr);
 118                 if (TASK_SIZE - len >= addr &&
 119                     (!vma || addr + len <= vma->vm_start))
 120                         return addr;
 121         }
 122
 123         start_addr = mm->free_area_cache;
 124
 125 full_search:
 126         addr = ALIGN(start_addr, HPAGE_SIZE);
 127
 128         for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
 129                 /* At this point:  (!vma || addr < vma->vm_end). */
 130                 if (TASK_SIZE - len < addr) {
 131                         /*
 132                          * Start a new search - just in case we missed
 133                          * some holes.
 134                          */
 135                         if (start_addr != TASK_UNMAPPED_BASE) {
 136                                 start_addr = TASK_UNMAPPED_BASE;
 137                                 goto full_search;
 138                         }
 139                         return -ENOMEM;
 140                 }
 141
 142                 if (!vma || addr + len <= vma->vm_start)
 143                         return addr;
 144                 addr = ALIGN(vma->vm_end, HPAGE_SIZE);
 145         }
 146 }
 147 #endif
 148
 149 /*
 150  * Read a page. Again trivial. If it didn't already exist
 151  * in the page cache, it is zero-filled.
 152  */
 153 static int hugetlbfs_readpage(struct file *file, struct page * page)
 154 {
 155         unlock_page(page);
 156         return -EINVAL;
 157 }
 158
 159 static int hugetlbfs_prepare_write(struct file *file,
 160                         struct page *page, unsigned offset, unsigned to)
 161 {
 162         return -EINVAL;
 163 }
 164
 165 static int hugetlbfs_commit_write(struct file *file,
 166                         struct page *page, unsigned offset, unsigned to)
 167 {
 168         return -EINVAL;
 169 }
 170
 171 static void huge_pagevec_release(struct pagevec *pvec)
 172 {
 173         int i;
 174
 175         for (i = 0; i < pagevec_count(pvec); ++i)
 176                 put_page(pvec->pages[i]);
 177
 178         pagevec_reinit(pvec);
 179 }
 180
 181 static void truncate_huge_page(struct page *page)
 182 {
 183         clear_page_dirty(page);
 184         ClearPageUptodate(page);
 185         remove_from_page_cache(page);
 186         put_page(page);
 187 }
 188
 189 static void truncate_hugepages(struct address_space *mapping, loff_t lstart)
 190 {
 191         const pgoff_t start = lstart >> HPAGE_SHIFT;
 192         struct pagevec pvec;
 193         pgoff_t next;
 194         int i;
 195
 196         pagevec_init(&pvec, 0);
 197         next = start;
 198         while (1) {
 199                 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
 200                         if (next == start)
 201                                 break;
 202                         next = start;
 203                         continue;
 204                 }
 205
 206                 for (i = 0; i < pagevec_count(&pvec); ++i) {
 207                         struct page *page = pvec.pages[i];
 208
 209                         lock_page(page);
 210                         if (page->index > next)
 211                                 next = page->index;
 212                         ++next;
 213                         truncate_huge_page(page);
 214                         unlock_page(page);
 215                         hugetlb_put_quota(mapping);
 216                 }
 217                 huge_pagevec_release(&pvec);
 218         }
 219         BUG_ON(!lstart && mapping->nrpages);
 220 }
 221
 222 static void hugetlbfs_delete_inode(struct inode *inode)
 223 {
 224         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(inode->i_sb);
 225
 226         hlist_del_init(&inode->i_hash);
 227         list_del_init(&inode->i_list);
 228         list_del_init(&inode->i_sb_list);
 229         inode->i_state |= I_FREEING;
 230         inodes_stat.nr_inodes--;
 231         spin_unlock(&inode_lock);
 232
 233         if (inode->i_data.nrpages)
 234                 truncate_hugepages(&inode->i_data, 0);
 235
 236         security_inode_delete(inode);
 237
 238         if (sbinfo->free_inodes >= 0) {
 239                 spin_lock(&sbinfo->stat_lock);
 240                 sbinfo->free_inodes++;
 241                 spin_unlock(&sbinfo->stat_lock);
 242         }
 243
 244         clear_inode(inode);
 245         destroy_inode(inode);
 246 }
 247
 248 static void hugetlbfs_forget_inode(struct inode *inode)
 249 {
 250         struct super_block *super_block = inode->i_sb;
 251         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(super_block);
 252
 253         if (hlist_unhashed(&inode->i_hash))
 254                 goto out_truncate;
 255
 256         if (!(inode->i_state & (I_DIRTY|I_LOCK))) {
 257                 list_del(&inode->i_list);
 258                 list_add(&inode->i_list, &inode_unused);
 259         }
 260         inodes_stat.nr_unused++;
 261         if (!super_block || (super_block->s_flags & MS_ACTIVE)) {
 262                 spin_unlock(&inode_lock);
 263                 return;
 264         }
 265
 266         /* write_inode_now() ? */
 267         inodes_stat.nr_unused--;
 268         hlist_del_init(&inode->i_hash);
 269 out_truncate:
 270         list_del_init(&inode->i_list);
 271         list_del_init(&inode->i_sb_list);
 272         inode->i_state |= I_FREEING;
 273         inodes_stat.nr_inodes--;
 274         spin_unlock(&inode_lock);
 275         if (inode->i_data.nrpages)
 276                 truncate_hugepages(&inode->i_data, 0);
 277
 278         if (sbinfo->free_inodes >= 0) {
 279                 spin_lock(&sbinfo->stat_lock);
 280                 sbinfo->free_inodes++;
 281                 spin_unlock(&sbinfo->stat_lock);
 282         }
 283
 284         clear_inode(inode);
 285         destroy_inode(inode);
 286 }
 287
 288 static void hugetlbfs_drop_inode(struct inode *inode)
 289 {
 290         if (!inode->i_nlink)
 291                 hugetlbfs_delete_inode(inode);
 292         else
 293                 hugetlbfs_forget_inode(inode);
 294 }
 295
 296 /*
 297  * h_pgoff is in HPAGE_SIZE units.
 298  * vma->vm_pgoff is in PAGE_SIZE units.
 299  */
 300 static inline void
 301 hugetlb_vmtruncate_list(struct prio_tree_root *root, unsigned long h_pgoff)
 302 {
 303         struct vm_area_struct *vma;
 304         struct prio_tree_iter iter;
 305
 306         vma_prio_tree_foreach(vma, &iter, root, h_pgoff, ULONG_MAX) {
 307                 unsigned long h_vm_pgoff;
 308                 unsigned long v_length;
 309                 unsigned long v_offset;
 310
 311                 h_vm_pgoff = vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT);
 312                 v_offset = (h_pgoff - h_vm_pgoff) << HPAGE_SHIFT;
 313                 /*
 314                  * Is this VMA fully outside the truncation point?
 315                  */
 316                 if (h_vm_pgoff >= h_pgoff)
 317                         v_offset = 0;
 318
 319                 v_length = vma->vm_end - vma->vm_start;
 320
 321                 zap_hugepage_range(vma,
 322                                 vma->vm_start + v_offset,
 323                                 v_length - v_offset);
 324         }
 325 }
 326
 327 /*
 328  * Expanding truncates are not allowed.
 329  */
 330 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
 331 {
 332         unsigned long pgoff;
 333         struct address_space *mapping = inode->i_mapping;
 334
 335         if (offset > inode->i_size)
 336                 return -EINVAL;
 337
 338         BUG_ON(offset & ~HPAGE_MASK);
 339         pgoff = offset >> HPAGE_SHIFT;
 340
 341         inode->i_size = offset;
 342         spin_lock(&mapping->i_mmap_lock);
 343         if (!prio_tree_empty(&mapping->i_mmap))
 344                 hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff);
 345         spin_unlock(&mapping->i_mmap_lock);
 346         truncate_hugepages(mapping, offset);
 347         return 0;
 348 }
 349
 350 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
 351 {
 352         struct inode *inode = dentry->d_inode;
 353         int error;
 354         unsigned int ia_valid = attr->ia_valid;
 355
 356         BUG_ON(!inode);
 357
 358         error = inode_change_ok(inode, attr);
 359         if (error)
 360                 goto out;
 361
 362         if (ia_valid & ATTR_SIZE) {
 363                 error = -EINVAL;
 364                 if (!(attr->ia_size & ~HPAGE_MASK))
 365                         error = hugetlb_vmtruncate(inode, attr->ia_size);
 366                 if (error)
 367                         goto out;
 368                 attr->ia_valid &= ~ATTR_SIZE;
 369         }
 370         error = inode_setattr(inode, attr);
 371 out:
 372         return error;
 373 }
 374
 375 static struct inode *hugetlbfs_get_inode(struct super_block *sb, uid_t uid,
 376                                         gid_t gid, int mode, dev_t dev)
 377 {
 378         struct inode *inode;
 379         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
 380
 381         if (sbinfo->free_inodes >= 0) {
 382                 spin_lock(&sbinfo->stat_lock);
 383                 if (!sbinfo->free_inodes) {
 384                         spin_unlock(&sbinfo->stat_lock);
 385                         return NULL;
 386                 }
 387                 sbinfo->free_inodes--;
 388                 spin_unlock(&sbinfo->stat_lock);
 389         }
 390
 391         inode = new_inode(sb);
 392         if (inode) {
 393                 struct hugetlbfs_inode_info *info;
 394                 inode->i_mode = mode;
 395                 inode->i_uid = uid;
 396                 inode->i_gid = gid;
 397                 inode->i_blksize = HPAGE_SIZE;
 398                 inode->i_blocks = 0;
 399                 inode->i_mapping->a_ops = &hugetlbfs_aops;
 400                 inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info;
 401                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 402                 info = HUGETLBFS_I(inode);
 403                 mpol_shared_policy_init(&info->policy);
 404                 switch (mode & S_IFMT) {
 405                 default:
 406                         init_special_inode(inode, mode, dev);
 407                         break;
 408                 case S_IFREG:
 409                         inode->i_op = &hugetlbfs_inode_operations;
 410                         inode->i_fop = &hugetlbfs_file_operations;
 411                         break;
 412                 case S_IFDIR:
 413                         inode->i_op = &hugetlbfs_dir_inode_operations;
 414                         inode->i_fop = &simple_dir_operations;
 415
 416                         /* directory inodes start off with i_nlink == 2 (for "." entry) */
 417                         inode->i_nlink++;
 418                         break;
 419                 case S_IFLNK:
 420                         inode->i_op = &page_symlink_inode_operations;
 421                         break;
 422                 }
 423         }
 424         return inode;
 425 }
 426
 427 /*
 428  * File creation. Allocate an inode, and we're done..
 429  */
 430 static int hugetlbfs_mknod(struct inode *dir,
 431                         struct dentry *dentry, int mode, dev_t dev)
 432 {
 433         struct inode *inode;
 434         int error = -ENOSPC;
 435         gid_t gid;
 436
 437         if (dir->i_mode & S_ISGID) {
 438                 gid = dir->i_gid;
 439                 if (S_ISDIR(mode))
 440                         mode |= S_ISGID;
 441         } else {
 442                 gid = current->fsgid;
 443         }
 444         inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid, gid, mode, dev);
 445         if (inode) {
 446                 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 447                 d_instantiate(dentry, inode);
 448                 dget(dentry);   /* Extra count - pin the dentry in core */
 449                 error = 0;
 450         }
 451         return error;
 452 }
 453
 454 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 455 {
 456         int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
 457         if (!retval)
 458                 dir->i_nlink++;
 459         return retval;
 460 }
 461
 462 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, int mode, struct nameidata *nd)
 463 {
 464         return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
 465 }
 466
 467 static int hugetlbfs_symlink(struct inode *dir,
 468                         struct dentry *dentry, const char *symname)
 469 {
 470         struct inode *inode;
 471         int error = -ENOSPC;
 472         gid_t gid;
 473
 474         if (dir->i_mode & S_ISGID)
 475                 gid = dir->i_gid;
 476         else
 477                 gid = current->fsgid;
 478
 479         inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid,
 480                                         gid, S_IFLNK|S_IRWXUGO, 0);
 481         if (inode) {
 482                 int l = strlen(symname)+1;
 483                 error = page_symlink(inode, symname, l);
 484                 if (!error) {
 485                         d_instantiate(dentry, inode);
 486                         dget(dentry);
 487                 } else
 488                         iput(inode);
 489         }
 490         dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 491
 492         return error;
 493 }
 494
 495 /*
 496  * For direct-IO reads into hugetlb pages
 497  */
 498 static int hugetlbfs_set_page_dirty(struct page *page)
 499 {
 500         return 0;
 501 }
 502
 503 static int hugetlbfs_statfs(struct super_block *sb, struct kstatfs *buf)
 504 {
 505         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
 506
 507         buf->f_type = HUGETLBFS_MAGIC;
 508         buf->f_bsize = HPAGE_SIZE;
 509         if (sbinfo) {
 510                 spin_lock(&sbinfo->stat_lock);
 511                 buf->f_blocks = sbinfo->max_blocks;
 512                 buf->f_bavail = buf->f_bfree = sbinfo->free_blocks;
 513                 buf->f_files = sbinfo->max_inodes;
 514                 buf->f_ffree = sbinfo->free_inodes;
 515                 spin_unlock(&sbinfo->stat_lock);
 516         }
 517         buf->f_namelen = NAME_MAX;
 518         return 0;
 519 }
 520
 521 static void hugetlbfs_put_super(struct super_block *sb)
 522 {
 523         struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
 524
 525         if (sbi) {
 526                 sb->s_fs_info = NULL;
 527                 kfree(sbi);
 528         }
 529 }
 530
 531 static kmem_cache_t *hugetlbfs_inode_cachep;
 532
 533 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
 534 {
 535         struct hugetlbfs_inode_info *p;
 536
 537         p = kmem_cache_alloc(hugetlbfs_inode_cachep, SLAB_KERNEL);
 538         if (!p)
 539                 return NULL;
 540         return &p->vfs_inode;
 541 }
 542
 543 static void init_once(void *foo, kmem_cache_t *cachep, unsigned long flags)
 544 {
 545         struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
 546
 547         if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
 548             SLAB_CTOR_CONSTRUCTOR)
 549                 inode_init_once(&ei->vfs_inode);
 550 }
 551
 552 static void hugetlbfs_destroy_inode(struct inode *inode)
 553 {
 554         mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
 555         kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
 556 }
 557
 558 static struct address_space_operations hugetlbfs_aops = {
 559         .readpage       = hugetlbfs_readpage,
 560         .prepare_write  = hugetlbfs_prepare_write,
 561         .commit_write   = hugetlbfs_commit_write,
 562         .set_page_dirty = hugetlbfs_set_page_dirty,
 563 };
 564
 565 struct file_operations hugetlbfs_file_operations = {
 566         .mmap                   = hugetlbfs_file_mmap,
 567         .fsync                  = simple_sync_file,
 568         .get_unmapped_area      = hugetlb_get_unmapped_area,
 569 };
 570
 571 static struct inode_operations hugetlbfs_dir_inode_operations = {
 572         .create         = hugetlbfs_create,
 573         .lookup         = simple_lookup,
 574         .link           = simple_link,
 575         .unlink         = simple_unlink,
 576         .symlink        = hugetlbfs_symlink,
 577         .mkdir          = hugetlbfs_mkdir,
 578         .rmdir          = simple_rmdir,
 579         .mknod          = hugetlbfs_mknod,
 580         .rename         = simple_rename,
 581         .setattr        = hugetlbfs_setattr,
 582 };
 583
 584 static struct inode_operations hugetlbfs_inode_operations = {
 585         .setattr        = hugetlbfs_setattr,
 586 };
 587
 588 static struct super_operations hugetlbfs_ops = {
 589         .alloc_inode    = hugetlbfs_alloc_inode,
 590         .destroy_inode  = hugetlbfs_destroy_inode,
 591         .statfs         = hugetlbfs_statfs,
 592         .drop_inode     = hugetlbfs_drop_inode,
 593         .put_super      = hugetlbfs_put_super,
 594 };
 595
 596 static int
 597 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
 598 {
 599         char *opt, *value, *rest;
 600
 601         if (!options)
 602                 return 0;
 603         while ((opt = strsep(&options, ",")) != NULL) {
 604                 if (!*opt)
 605                         continue;
 606
 607                 value = strchr(opt, '=');
 608                 if (!value || !*value)
 609                         return -EINVAL;
 610                 else
 611                         *value++ = '\0';
 612
 613                 if (!strcmp(opt, "uid"))
 614                         pconfig->uid = simple_strtoul(value, &value, 0);
 615                 else if (!strcmp(opt, "gid"))
 616                         pconfig->gid = simple_strtoul(value, &value, 0);
 617                 else if (!strcmp(opt, "mode"))
 618                         pconfig->mode = simple_strtoul(value,&value,0) & 0777U;
 619                 else if (!strcmp(opt, "size")) {
 620                         unsigned long long size = memparse(value, &rest);
 621                         if (*rest == '%') {
 622                                 size <<= HPAGE_SHIFT;
 623                                 size *= max_huge_pages;
 624                                 do_div(size, 100);
 625                                 rest++;
 626                         }
 627                         size &= HPAGE_MASK;
 628                         pconfig->nr_blocks = (size >> HPAGE_SHIFT);
 629                         value = rest;
 630                 } else if (!strcmp(opt,"nr_inodes")) {
 631                         pconfig->nr_inodes = memparse(value, &rest);
 632                         value = rest;
 633                 } else
 634                         return -EINVAL;
 635
 636                 if (*value)
 637                         return -EINVAL;
 638         }
 639         return 0;
 640 }
 641
 642 static int
 643 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
 644 {
 645         struct inode * inode;
 646         struct dentry * root;
 647         int ret;
 648         struct hugetlbfs_config config;
 649         struct hugetlbfs_sb_info *sbinfo;
 650
 651         config.nr_blocks = -1; /* No limit on size by default */
 652         config.nr_inodes = -1; /* No limit on number of inodes by default */
 653         config.uid = current->fsuid;
 654         config.gid = current->fsgid;
 655         config.mode = 0755;
 656         ret = hugetlbfs_parse_options(data, &config);
 657
 658         if (ret)
 659                 return ret;
 660
 661         sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
 662         if (!sbinfo)
 663                 return -ENOMEM;
 664         sb->s_fs_info = sbinfo;
 665         spin_lock_init(&sbinfo->stat_lock);
 666         sbinfo->max_blocks = config.nr_blocks;
 667         sbinfo->free_blocks = config.nr_blocks;
 668         sbinfo->max_inodes = config.nr_inodes;
 669         sbinfo->free_inodes = config.nr_inodes;
 670         sb->s_maxbytes = MAX_LFS_FILESIZE;
 671         sb->s_blocksize = HPAGE_SIZE;
 672         sb->s_blocksize_bits = HPAGE_SHIFT;
 673         sb->s_magic = HUGETLBFS_MAGIC;
 674         sb->s_op = &hugetlbfs_ops;
 675         sb->s_time_gran = 1;
 676         inode = hugetlbfs_get_inode(sb, config.uid, config.gid,
 677                                         S_IFDIR | config.mode, 0);
 678         if (!inode)
 679                 goto out_free;
 680
 681         root = d_alloc_root(inode);
 682         if (!root) {
 683                 iput(inode);
 684                 goto out_free;
 685         }
 686         sb->s_root = root;
 687         return 0;
 688 out_free:
 689         kfree(sbinfo);
 690         return -ENOMEM;
 691 }
 692
 693 int hugetlb_get_quota(struct address_space *mapping)
 694 {
 695         int ret = 0;
 696         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
 697
 698         if (sbinfo->free_blocks > -1) {
 699                 spin_lock(&sbinfo->stat_lock);
 700                 if (sbinfo->free_blocks > 0)
 701                         sbinfo->free_blocks--;
 702                 else
 703                         ret = -ENOMEM;
 704                 spin_unlock(&sbinfo->stat_lock);
 705         }
 706
 707         return ret;
 708 }
 709
 710 void hugetlb_put_quota(struct address_space *mapping)
 711 {
 712         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
 713
 714         if (sbinfo->free_blocks > -1) {
 715                 spin_lock(&sbinfo->stat_lock);
 716                 sbinfo->free_blocks++;
 717                 spin_unlock(&sbinfo->stat_lock);
 718         }
 719 }
 720
 721 static struct super_block *hugetlbfs_get_sb(struct file_system_type *fs_type,
 722         int flags, const char *dev_name, void *data)
 723 {
 724         return get_sb_nodev(fs_type, flags, data, hugetlbfs_fill_super);
 725 }
 726
 727 static struct file_system_type hugetlbfs_fs_type = {
 728         .name           = "hugetlbfs",
 729         .get_sb         = hugetlbfs_get_sb,
 730         .kill_sb        = kill_litter_super,
 731 };
 732
 733 static struct vfsmount *hugetlbfs_vfsmount;
 734
 735 /*
 736  * Return the next identifier for a shm file
 737  */
 738 static unsigned long hugetlbfs_counter(void)
 739 {
 740         static DEFINE_SPINLOCK(lock);
 741         static unsigned long counter;
 742         unsigned long ret;
 743
 744         spin_lock(&lock);
 745         ret = ++counter;
 746         spin_unlock(&lock);
 747         return ret;
 748 }
 749
 750 static int can_do_hugetlb_shm(void)
 751 {
 752         return likely(capable(CAP_IPC_LOCK) ||
 753                         in_group_p(sysctl_hugetlb_shm_group) ||
 754                         can_do_mlock());
 755 }
 756
 757 struct file *hugetlb_zero_setup(size_t size)
 758 {
 759         int error = -ENOMEM;
 760         struct file *file;
 761         struct inode *inode;
 762         struct dentry *dentry, *root;
 763         struct qstr quick_string;
 764         char buf[16];
 765
 766         if (!can_do_hugetlb_shm())
 767                 return ERR_PTR(-EPERM);
 768
 769         if (!is_hugepage_mem_enough(size))
 770                 return ERR_PTR(-ENOMEM);
 771
 772         if (!user_shm_lock(size, current->user))
 773                 return ERR_PTR(-ENOMEM);
 774
 775         root = hugetlbfs_vfsmount->mnt_root;
 776         snprintf(buf, 16, "%lu", hugetlbfs_counter());
 777         quick_string.name = buf;
 778         quick_string.len = strlen(quick_string.name);
 779         quick_string.hash = 0;
 780         dentry = d_alloc(root, &quick_string);
 781         if (!dentry)
 782                 goto out_shm_unlock;
 783
 784         error = -ENFILE;
 785         file = get_empty_filp();
 786         if (!file)
 787                 goto out_dentry;
 788
 789         error = -ENOSPC;
 790         inode = hugetlbfs_get_inode(root->d_sb, current->fsuid,
 791                                 current->fsgid, S_IFREG | S_IRWXUGO, 0);
 792         if (!inode)
 793                 goto out_file;
 794
 795         d_instantiate(dentry, inode);
 796         inode->i_size = size;
 797         inode->i_nlink = 0;
 798         file->f_vfsmnt = mntget(hugetlbfs_vfsmount);
 799         file->f_dentry = dentry;
 800         file->f_mapping = inode->i_mapping;
 801         file->f_op = &hugetlbfs_file_operations;
 802         file->f_mode = FMODE_WRITE | FMODE_READ;
 803         return file;
 804
 805 out_file:
 806         put_filp(file);
 807 out_dentry:
 808         dput(dentry);
 809 out_shm_unlock:
 810         user_shm_unlock(size, current->user);
 811         return ERR_PTR(error);
 812 }
 813
 814 static int __init init_hugetlbfs_fs(void)
 815 {
 816         int error;
 817         struct vfsmount *vfsmount;
 818
 819         hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
 820                                         sizeof(struct hugetlbfs_inode_info),
 821                                         0, 0, init_once, NULL);
 822         if (hugetlbfs_inode_cachep == NULL)
 823                 return -ENOMEM;
 824
 825         error = register_filesystem(&hugetlbfs_fs_type);
 826         if (error)
 827                 goto out;
 828
 829         vfsmount = kern_mount(&hugetlbfs_fs_type);
 830
 831         if (!IS_ERR(vfsmount)) {
 832                 hugetlbfs_vfsmount = vfsmount;
 833                 return 0;
 834         }
 835
 836         error = PTR_ERR(vfsmount);
 837
 838  out:
 839         if (error)
 840                 kmem_cache_destroy(hugetlbfs_inode_cachep);
 841         return error;
 842 }
 843
 844 static void __exit exit_hugetlbfs_fs(void)
 845 {
 846         kmem_cache_destroy(hugetlbfs_inode_cachep);
 847         unregister_filesystem(&hugetlbfs_fs_type);
 848 }
 849
 850 module_init(init_hugetlbfs_fs)
 851 module_exit(exit_hugetlbfs_fs)
 852
 853 MODULE_LICENSE("GPL");