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 void huge_pagevec_release(struct pagevec *pvec)
  49 {
  50         int i;
  51
  52         for (i = 0; i < pagevec_count(pvec); ++i)
  53                 put_page(pvec->pages[i]);
  54
  55         pagevec_reinit(pvec);
  56 }
  57
  58 /*
  59  * huge_pages_needed tries to determine the number of new huge pages that
  60  * will be required to fully populate this VMA.  This will be equal to
  61  * the size of the VMA in huge pages minus the number of huge pages
  62  * (covered by this VMA) that are found in the page cache.
  63  *
  64  * Result is in bytes to be compatible with is_hugepage_mem_enough()
  65  */
  66 static unsigned long
  67 huge_pages_needed(struct address_space *mapping, struct vm_area_struct *vma)
  68 {
  69         int i;
  70         struct pagevec pvec;
  71         unsigned long start = vma->vm_start;
  72         unsigned long end = vma->vm_end;
  73         unsigned long hugepages = (end - start) >> HPAGE_SHIFT;
  74         pgoff_t next = vma->vm_pgoff;
  75         pgoff_t endpg = next + ((end - start) >> PAGE_SHIFT);
  76
  77         pagevec_init(&pvec, 0);
  78         while (next < endpg) {
  79                 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE))
  80                         break;
  81                 for (i = 0; i < pagevec_count(&pvec); i++) {
  82                         struct page *page = pvec.pages[i];
  83                         if (page->index > next)
  84                                 next = page->index;
  85                         if (page->index >= endpg)
  86                                 break;
  87                         next++;
  88                         hugepages--;
  89                 }
  90                 huge_pagevec_release(&pvec);
  91         }
  92         return hugepages << HPAGE_SHIFT;
  93 }
  94
  95 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
  96 {
  97         struct inode *inode = file->f_dentry->d_inode;
  98         struct address_space *mapping = inode->i_mapping;
  99         unsigned long bytes;
 100         loff_t len, vma_len;
 101         int ret;
 102
 103         if (vma->vm_pgoff & (HPAGE_SIZE / PAGE_SIZE - 1))
 104                 return -EINVAL;
 105
 106         if (vma->vm_start & ~HPAGE_MASK)
 107                 return -EINVAL;
 108
 109         if (vma->vm_end & ~HPAGE_MASK)
 110                 return -EINVAL;
 111
 112         if (vma->vm_end - vma->vm_start < HPAGE_SIZE)
 113                 return -EINVAL;
 114
 115         bytes = huge_pages_needed(mapping, vma);
 116         if (!is_hugepage_mem_enough(bytes))
 117                 return -ENOMEM;
 118
 119         vma_len = (loff_t)(vma->vm_end - vma->vm_start);
 120
 121         mutex_lock(&inode->i_mutex);
 122         file_accessed(file);
 123         vma->vm_flags |= VM_HUGETLB | VM_RESERVED;
 124         vma->vm_ops = &hugetlb_vm_ops;
 125
 126         ret = -ENOMEM;
 127         len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
 128         if (!(vma->vm_flags & VM_WRITE) && len > inode->i_size)
 129                 goto out;
 130
 131         ret = 0;
 132         hugetlb_prefault_arch_hook(vma->vm_mm);
 133         if (inode->i_size < len)
 134                 inode->i_size = len;
 135 out:
 136         mutex_unlock(&inode->i_mutex);
 137
 138         return ret;
 139 }
 140
 141 /*
 142  * Called under down_write(mmap_sem).
 143  */
 144
 145 #ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
 146 unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 147                 unsigned long len, unsigned long pgoff, unsigned long flags);
 148 #else
 149 static unsigned long
 150 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 151                 unsigned long len, unsigned long pgoff, unsigned long flags)
 152 {
 153         struct mm_struct *mm = current->mm;
 154         struct vm_area_struct *vma;
 155         unsigned long start_addr;
 156
 157         if (len & ~HPAGE_MASK)
 158                 return -EINVAL;
 159         if (len > TASK_SIZE)
 160                 return -ENOMEM;
 161
 162         if (addr) {
 163                 addr = ALIGN(addr, HPAGE_SIZE);
 164                 vma = find_vma(mm, addr);
 165                 if (TASK_SIZE - len >= addr &&
 166                     (!vma || addr + len <= vma->vm_start))
 167                         return addr;
 168         }
 169
 170         start_addr = mm->free_area_cache;
 171
 172         if (len <= mm->cached_hole_size)
 173                 start_addr = TASK_UNMAPPED_BASE;
 174
 175 full_search:
 176         addr = ALIGN(start_addr, HPAGE_SIZE);
 177
 178         for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
 179                 /* At this point:  (!vma || addr < vma->vm_end). */
 180                 if (TASK_SIZE - len < addr) {
 181                         /*
 182                          * Start a new search - just in case we missed
 183                          * some holes.
 184                          */
 185                         if (start_addr != TASK_UNMAPPED_BASE) {
 186                                 start_addr = TASK_UNMAPPED_BASE;
 187                                 goto full_search;
 188                         }
 189                         return -ENOMEM;
 190                 }
 191
 192                 if (!vma || addr + len <= vma->vm_start)
 193                         return addr;
 194                 addr = ALIGN(vma->vm_end, HPAGE_SIZE);
 195         }
 196 }
 197 #endif
 198
 199 /*
 200  * Read a page. Again trivial. If it didn't already exist
 201  * in the page cache, it is zero-filled.
 202  */
 203 static int hugetlbfs_readpage(struct file *file, struct page * page)
 204 {
 205         unlock_page(page);
 206         return -EINVAL;
 207 }
 208
 209 static int hugetlbfs_prepare_write(struct file *file,
 210                         struct page *page, unsigned offset, unsigned to)
 211 {
 212         return -EINVAL;
 213 }
 214
 215 static int hugetlbfs_commit_write(struct file *file,
 216                         struct page *page, unsigned offset, unsigned to)
 217 {
 218         return -EINVAL;
 219 }
 220
 221 static void truncate_huge_page(struct page *page)
 222 {
 223         clear_page_dirty(page);
 224         ClearPageUptodate(page);
 225         remove_from_page_cache(page);
 226         put_page(page);
 227 }
 228
 229 static void truncate_hugepages(struct address_space *mapping, loff_t lstart)
 230 {
 231         const pgoff_t start = lstart >> HPAGE_SHIFT;
 232         struct pagevec pvec;
 233         pgoff_t next;
 234         int i;
 235
 236         pagevec_init(&pvec, 0);
 237         next = start;
 238         while (1) {
 239                 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
 240                         if (next == start)
 241                                 break;
 242                         next = start;
 243                         continue;
 244                 }
 245
 246                 for (i = 0; i < pagevec_count(&pvec); ++i) {
 247                         struct page *page = pvec.pages[i];
 248
 249                         lock_page(page);
 250                         if (page->index > next)
 251                                 next = page->index;
 252                         ++next;
 253                         truncate_huge_page(page);
 254                         unlock_page(page);
 255                         hugetlb_put_quota(mapping);
 256                 }
 257                 huge_pagevec_release(&pvec);
 258         }
 259         BUG_ON(!lstart && mapping->nrpages);
 260 }
 261
 262 static void hugetlbfs_delete_inode(struct inode *inode)
 263 {
 264         if (inode->i_data.nrpages)
 265                 truncate_hugepages(&inode->i_data, 0);
 266         clear_inode(inode);
 267 }
 268
 269 static void hugetlbfs_forget_inode(struct inode *inode)
 270 {
 271         struct super_block *sb = inode->i_sb;
 272
 273         if (!hlist_unhashed(&inode->i_hash)) {
 274                 if (!(inode->i_state & (I_DIRTY|I_LOCK)))
 275                         list_move(&inode->i_list, &inode_unused);
 276                 inodes_stat.nr_unused++;
 277                 if (!sb || (sb->s_flags & MS_ACTIVE)) {
 278                         spin_unlock(&inode_lock);
 279                         return;
 280                 }
 281                 inode->i_state |= I_WILL_FREE;
 282                 spin_unlock(&inode_lock);
 283                 /*
 284                  * write_inode_now is a noop as we set BDI_CAP_NO_WRITEBACK
 285                  * in our backing_dev_info.
 286                  */
 287                 write_inode_now(inode, 1);
 288                 spin_lock(&inode_lock);
 289                 inode->i_state &= ~I_WILL_FREE;
 290                 inodes_stat.nr_unused--;
 291                 hlist_del_init(&inode->i_hash);
 292         }
 293         list_del_init(&inode->i_list);
 294         list_del_init(&inode->i_sb_list);
 295         inode->i_state |= I_FREEING;
 296         inodes_stat.nr_inodes--;
 297         spin_unlock(&inode_lock);
 298         if (inode->i_data.nrpages)
 299                 truncate_hugepages(&inode->i_data, 0);
 300         clear_inode(inode);
 301         destroy_inode(inode);
 302 }
 303
 304 static void hugetlbfs_drop_inode(struct inode *inode)
 305 {
 306         if (!inode->i_nlink)
 307                 generic_delete_inode(inode);
 308         else
 309                 hugetlbfs_forget_inode(inode);
 310 }
 311
 312 /*
 313  * h_pgoff is in HPAGE_SIZE units.
 314  * vma->vm_pgoff is in PAGE_SIZE units.
 315  */
 316 static inline void
 317 hugetlb_vmtruncate_list(struct prio_tree_root *root, unsigned long h_pgoff)
 318 {
 319         struct vm_area_struct *vma;
 320         struct prio_tree_iter iter;
 321
 322         vma_prio_tree_foreach(vma, &iter, root, h_pgoff, ULONG_MAX) {
 323                 unsigned long h_vm_pgoff;
 324                 unsigned long v_offset;
 325
 326                 h_vm_pgoff = vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT);
 327                 v_offset = (h_pgoff - h_vm_pgoff) << HPAGE_SHIFT;
 328                 /*
 329                  * Is this VMA fully outside the truncation point?
 330                  */
 331                 if (h_vm_pgoff >= h_pgoff)
 332                         v_offset = 0;
 333
 334                 unmap_hugepage_range(vma,
 335                                 vma->vm_start + v_offset, vma->vm_end);
 336         }
 337 }
 338
 339 /*
 340  * Expanding truncates are not allowed.
 341  */
 342 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
 343 {
 344         unsigned long pgoff;
 345         struct address_space *mapping = inode->i_mapping;
 346
 347         if (offset > inode->i_size)
 348                 return -EINVAL;
 349
 350         BUG_ON(offset & ~HPAGE_MASK);
 351         pgoff = offset >> HPAGE_SHIFT;
 352
 353         inode->i_size = offset;
 354         spin_lock(&mapping->i_mmap_lock);
 355         if (!prio_tree_empty(&mapping->i_mmap))
 356                 hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff);
 357         spin_unlock(&mapping->i_mmap_lock);
 358         truncate_hugepages(mapping, offset);
 359         return 0;
 360 }
 361
 362 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
 363 {
 364         struct inode *inode = dentry->d_inode;
 365         int error;
 366         unsigned int ia_valid = attr->ia_valid;
 367
 368         BUG_ON(!inode);
 369
 370         error = inode_change_ok(inode, attr);
 371         if (error)
 372                 goto out;
 373
 374         if (ia_valid & ATTR_SIZE) {
 375                 error = -EINVAL;
 376                 if (!(attr->ia_size & ~HPAGE_MASK))
 377                         error = hugetlb_vmtruncate(inode, attr->ia_size);
 378                 if (error)
 379                         goto out;
 380                 attr->ia_valid &= ~ATTR_SIZE;
 381         }
 382         error = inode_setattr(inode, attr);
 383 out:
 384         return error;
 385 }
 386
 387 static struct inode *hugetlbfs_get_inode(struct super_block *sb, uid_t uid,
 388                                         gid_t gid, int mode, dev_t dev)
 389 {
 390         struct inode *inode;
 391
 392         inode = new_inode(sb);
 393         if (inode) {
 394                 struct hugetlbfs_inode_info *info;
 395                 inode->i_mode = mode;
 396                 inode->i_uid = uid;
 397                 inode->i_gid = gid;
 398                 inode->i_blksize = HPAGE_SIZE;
 399                 inode->i_blocks = 0;
 400                 inode->i_mapping->a_ops = &hugetlbfs_aops;
 401                 inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info;
 402                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 403                 info = HUGETLBFS_I(inode);
 404                 mpol_shared_policy_init(&info->policy);
 405                 switch (mode & S_IFMT) {
 406                 default:
 407                         init_special_inode(inode, mode, dev);
 408                         break;
 409                 case S_IFREG:
 410                         inode->i_op = &hugetlbfs_inode_operations;
 411                         inode->i_fop = &hugetlbfs_file_operations;
 412                         break;
 413                 case S_IFDIR:
 414                         inode->i_op = &hugetlbfs_dir_inode_operations;
 415                         inode->i_fop = &simple_dir_operations;
 416
 417                         /* directory inodes start off with i_nlink == 2 (for "." entry) */
 418                         inode->i_nlink++;
 419                         break;
 420                 case S_IFLNK:
 421                         inode->i_op = &page_symlink_inode_operations;
 422                         break;
 423                 }
 424         }
 425         return inode;
 426 }
 427
 428 /*
 429  * File creation. Allocate an inode, and we're done..
 430  */
 431 static int hugetlbfs_mknod(struct inode *dir,
 432                         struct dentry *dentry, int mode, dev_t dev)
 433 {
 434         struct inode *inode;
 435         int error = -ENOSPC;
 436         gid_t gid;
 437
 438         if (dir->i_mode & S_ISGID) {
 439                 gid = dir->i_gid;
 440                 if (S_ISDIR(mode))
 441                         mode |= S_ISGID;
 442         } else {
 443                 gid = current->fsgid;
 444         }
 445         inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid, gid, mode, dev);
 446         if (inode) {
 447                 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 448                 d_instantiate(dentry, inode);
 449                 dget(dentry);   /* Extra count - pin the dentry in core */
 450                 error = 0;
 451         }
 452         return error;
 453 }
 454
 455 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 456 {
 457         int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
 458         if (!retval)
 459                 dir->i_nlink++;
 460         return retval;
 461 }
 462
 463 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, int mode, struct nameidata *nd)
 464 {
 465         return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
 466 }
 467
 468 static int hugetlbfs_symlink(struct inode *dir,
 469                         struct dentry *dentry, const char *symname)
 470 {
 471         struct inode *inode;
 472         int error = -ENOSPC;
 473         gid_t gid;
 474
 475         if (dir->i_mode & S_ISGID)
 476                 gid = dir->i_gid;
 477         else
 478                 gid = current->fsgid;
 479
 480         inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid,
 481                                         gid, S_IFLNK|S_IRWXUGO, 0);
 482         if (inode) {
 483                 int l = strlen(symname)+1;
 484                 error = page_symlink(inode, symname, l);
 485                 if (!error) {
 486                         d_instantiate(dentry, inode);
 487                         dget(dentry);
 488                 } else
 489                         iput(inode);
 490         }
 491         dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 492
 493         return error;
 494 }
 495
 496 /*
 497  * For direct-IO reads into hugetlb pages
 498  */
 499 static int hugetlbfs_set_page_dirty(struct page *page)
 500 {
 501         return 0;
 502 }
 503
 504 static int hugetlbfs_statfs(struct super_block *sb, struct kstatfs *buf)
 505 {
 506         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
 507
 508         buf->f_type = HUGETLBFS_MAGIC;
 509         buf->f_bsize = HPAGE_SIZE;
 510         if (sbinfo) {
 511                 spin_lock(&sbinfo->stat_lock);
 512                 /* If no limits set, just report 0 for max/free/used
 513                  * blocks, like simple_statfs() */
 514                 if (sbinfo->max_blocks >= 0) {
 515                         buf->f_blocks = sbinfo->max_blocks;
 516                         buf->f_bavail = buf->f_bfree = sbinfo->free_blocks;
 517                         buf->f_files = sbinfo->max_inodes;
 518                         buf->f_ffree = sbinfo->free_inodes;
 519                 }
 520                 spin_unlock(&sbinfo->stat_lock);
 521         }
 522         buf->f_namelen = NAME_MAX;
 523         return 0;
 524 }
 525
 526 static void hugetlbfs_put_super(struct super_block *sb)
 527 {
 528         struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
 529
 530         if (sbi) {
 531                 sb->s_fs_info = NULL;
 532                 kfree(sbi);
 533         }
 534 }
 535
 536 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
 537 {
 538         if (sbinfo->free_inodes >= 0) {
 539                 spin_lock(&sbinfo->stat_lock);
 540                 if (unlikely(!sbinfo->free_inodes)) {
 541                         spin_unlock(&sbinfo->stat_lock);
 542                         return 0;
 543                 }
 544                 sbinfo->free_inodes--;
 545                 spin_unlock(&sbinfo->stat_lock);
 546         }
 547
 548         return 1;
 549 }
 550
 551 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
 552 {
 553         if (sbinfo->free_inodes >= 0) {
 554                 spin_lock(&sbinfo->stat_lock);
 555                 sbinfo->free_inodes++;
 556                 spin_unlock(&sbinfo->stat_lock);
 557         }
 558 }
 559
 560
 561 static kmem_cache_t *hugetlbfs_inode_cachep;
 562
 563 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
 564 {
 565         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
 566         struct hugetlbfs_inode_info *p;
 567
 568         if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
 569                 return NULL;
 570         p = kmem_cache_alloc(hugetlbfs_inode_cachep, SLAB_KERNEL);
 571         if (unlikely(!p)) {
 572                 hugetlbfs_inc_free_inodes(sbinfo);
 573                 return NULL;
 574         }
 575         return &p->vfs_inode;
 576 }
 577
 578 static void hugetlbfs_destroy_inode(struct inode *inode)
 579 {
 580         hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
 581         mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
 582         kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
 583 }
 584
 585 static struct address_space_operations hugetlbfs_aops = {
 586         .readpage       = hugetlbfs_readpage,
 587         .prepare_write  = hugetlbfs_prepare_write,
 588         .commit_write   = hugetlbfs_commit_write,
 589         .set_page_dirty = hugetlbfs_set_page_dirty,
 590 };
 591
 592
 593 static void init_once(void *foo, kmem_cache_t *cachep, unsigned long flags)
 594 {
 595         struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
 596
 597         if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
 598             SLAB_CTOR_CONSTRUCTOR)
 599                 inode_init_once(&ei->vfs_inode);
 600 }
 601
 602 struct file_operations hugetlbfs_file_operations = {
 603         .mmap                   = hugetlbfs_file_mmap,
 604         .fsync                  = simple_sync_file,
 605         .get_unmapped_area      = hugetlb_get_unmapped_area,
 606 };
 607
 608 static struct inode_operations hugetlbfs_dir_inode_operations = {
 609         .create         = hugetlbfs_create,
 610         .lookup         = simple_lookup,
 611         .link           = simple_link,
 612         .unlink         = simple_unlink,
 613         .symlink        = hugetlbfs_symlink,
 614         .mkdir          = hugetlbfs_mkdir,
 615         .rmdir          = simple_rmdir,
 616         .mknod          = hugetlbfs_mknod,
 617         .rename         = simple_rename,
 618         .setattr        = hugetlbfs_setattr,
 619 };
 620
 621 static struct inode_operations hugetlbfs_inode_operations = {
 622         .setattr        = hugetlbfs_setattr,
 623 };
 624
 625 static struct super_operations hugetlbfs_ops = {
 626         .alloc_inode    = hugetlbfs_alloc_inode,
 627         .destroy_inode  = hugetlbfs_destroy_inode,
 628         .statfs         = hugetlbfs_statfs,
 629         .delete_inode   = hugetlbfs_delete_inode,
 630         .drop_inode     = hugetlbfs_drop_inode,
 631         .put_super      = hugetlbfs_put_super,
 632 };
 633
 634 static int
 635 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
 636 {
 637         char *opt, *value, *rest;
 638
 639         if (!options)
 640                 return 0;
 641         while ((opt = strsep(&options, ",")) != NULL) {
 642                 if (!*opt)
 643                         continue;
 644
 645                 value = strchr(opt, '=');
 646                 if (!value || !*value)
 647                         return -EINVAL;
 648                 else
 649                         *value++ = '\0';
 650
 651                 if (!strcmp(opt, "uid"))
 652                         pconfig->uid = simple_strtoul(value, &value, 0);
 653                 else if (!strcmp(opt, "gid"))
 654                         pconfig->gid = simple_strtoul(value, &value, 0);
 655                 else if (!strcmp(opt, "mode"))
 656                         pconfig->mode = simple_strtoul(value,&value,0) & 0777U;
 657                 else if (!strcmp(opt, "size")) {
 658                         unsigned long long size = memparse(value, &rest);
 659                         if (*rest == '%') {
 660                                 size <<= HPAGE_SHIFT;
 661                                 size *= max_huge_pages;
 662                                 do_div(size, 100);
 663                                 rest++;
 664                         }
 665                         size &= HPAGE_MASK;
 666                         pconfig->nr_blocks = (size >> HPAGE_SHIFT);
 667                         value = rest;
 668                 } else if (!strcmp(opt,"nr_inodes")) {
 669                         pconfig->nr_inodes = memparse(value, &rest);
 670                         value = rest;
 671                 } else
 672                         return -EINVAL;
 673
 674                 if (*value)
 675                         return -EINVAL;
 676         }
 677         return 0;
 678 }
 679
 680 static int
 681 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
 682 {
 683         struct inode * inode;
 684         struct dentry * root;
 685         int ret;
 686         struct hugetlbfs_config config;
 687         struct hugetlbfs_sb_info *sbinfo;
 688
 689         config.nr_blocks = -1; /* No limit on size by default */
 690         config.nr_inodes = -1; /* No limit on number of inodes by default */
 691         config.uid = current->fsuid;
 692         config.gid = current->fsgid;
 693         config.mode = 0755;
 694         ret = hugetlbfs_parse_options(data, &config);
 695
 696         if (ret)
 697                 return ret;
 698
 699         sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
 700         if (!sbinfo)
 701                 return -ENOMEM;
 702         sb->s_fs_info = sbinfo;
 703         spin_lock_init(&sbinfo->stat_lock);
 704         sbinfo->max_blocks = config.nr_blocks;
 705         sbinfo->free_blocks = config.nr_blocks;
 706         sbinfo->max_inodes = config.nr_inodes;
 707         sbinfo->free_inodes = config.nr_inodes;
 708         sb->s_maxbytes = MAX_LFS_FILESIZE;
 709         sb->s_blocksize = HPAGE_SIZE;
 710         sb->s_blocksize_bits = HPAGE_SHIFT;
 711         sb->s_magic = HUGETLBFS_MAGIC;
 712         sb->s_op = &hugetlbfs_ops;
 713         sb->s_time_gran = 1;
 714         inode = hugetlbfs_get_inode(sb, config.uid, config.gid,
 715                                         S_IFDIR | config.mode, 0);
 716         if (!inode)
 717                 goto out_free;
 718
 719         root = d_alloc_root(inode);
 720         if (!root) {
 721                 iput(inode);
 722                 goto out_free;
 723         }
 724         sb->s_root = root;
 725         return 0;
 726 out_free:
 727         kfree(sbinfo);
 728         return -ENOMEM;
 729 }
 730
 731 int hugetlb_get_quota(struct address_space *mapping)
 732 {
 733         int ret = 0;
 734         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
 735
 736         if (sbinfo->free_blocks > -1) {
 737                 spin_lock(&sbinfo->stat_lock);
 738                 if (sbinfo->free_blocks > 0)
 739                         sbinfo->free_blocks--;
 740                 else
 741                         ret = -ENOMEM;
 742                 spin_unlock(&sbinfo->stat_lock);
 743         }
 744
 745         return ret;
 746 }
 747
 748 void hugetlb_put_quota(struct address_space *mapping)
 749 {
 750         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
 751
 752         if (sbinfo->free_blocks > -1) {
 753                 spin_lock(&sbinfo->stat_lock);
 754                 sbinfo->free_blocks++;
 755                 spin_unlock(&sbinfo->stat_lock);
 756         }
 757 }
 758
 759 static struct super_block *hugetlbfs_get_sb(struct file_system_type *fs_type,
 760         int flags, const char *dev_name, void *data)
 761 {
 762         return get_sb_nodev(fs_type, flags, data, hugetlbfs_fill_super);
 763 }
 764
 765 static struct file_system_type hugetlbfs_fs_type = {
 766         .name           = "hugetlbfs",
 767         .get_sb         = hugetlbfs_get_sb,
 768         .kill_sb        = kill_litter_super,
 769 };
 770
 771 static struct vfsmount *hugetlbfs_vfsmount;
 772
 773 /*
 774  * Return the next identifier for a shm file
 775  */
 776 static unsigned long hugetlbfs_counter(void)
 777 {
 778         static DEFINE_SPINLOCK(lock);
 779         static unsigned long counter;
 780         unsigned long ret;
 781
 782         spin_lock(&lock);
 783         ret = ++counter;
 784         spin_unlock(&lock);
 785         return ret;
 786 }
 787
 788 static int can_do_hugetlb_shm(void)
 789 {
 790         return likely(capable(CAP_IPC_LOCK) ||
 791                         in_group_p(sysctl_hugetlb_shm_group) ||
 792                         can_do_mlock());
 793 }
 794
 795 struct file *hugetlb_zero_setup(size_t size)
 796 {
 797         int error = -ENOMEM;
 798         struct file *file;
 799         struct inode *inode;
 800         struct dentry *dentry, *root;
 801         struct qstr quick_string;
 802         char buf[16];
 803
 804         if (!can_do_hugetlb_shm())
 805                 return ERR_PTR(-EPERM);
 806
 807         if (!is_hugepage_mem_enough(size))
 808                 return ERR_PTR(-ENOMEM);
 809
 810         if (!user_shm_lock(size, current->user))
 811                 return ERR_PTR(-ENOMEM);
 812
 813         root = hugetlbfs_vfsmount->mnt_root;
 814         snprintf(buf, 16, "%lu", hugetlbfs_counter());
 815         quick_string.name = buf;
 816         quick_string.len = strlen(quick_string.name);
 817         quick_string.hash = 0;
 818         dentry = d_alloc(root, &quick_string);
 819         if (!dentry)
 820                 goto out_shm_unlock;
 821
 822         error = -ENFILE;
 823         file = get_empty_filp();
 824         if (!file)
 825                 goto out_dentry;
 826
 827         error = -ENOSPC;
 828         inode = hugetlbfs_get_inode(root->d_sb, current->fsuid,
 829                                 current->fsgid, S_IFREG | S_IRWXUGO, 0);
 830         if (!inode)
 831                 goto out_file;
 832
 833         d_instantiate(dentry, inode);
 834         inode->i_size = size;
 835         inode->i_nlink = 0;
 836         file->f_vfsmnt = mntget(hugetlbfs_vfsmount);
 837         file->f_dentry = dentry;
 838         file->f_mapping = inode->i_mapping;
 839         file->f_op = &hugetlbfs_file_operations;
 840         file->f_mode = FMODE_WRITE | FMODE_READ;
 841         return file;
 842
 843 out_file:
 844         put_filp(file);
 845 out_dentry:
 846         dput(dentry);
 847 out_shm_unlock:
 848         user_shm_unlock(size, current->user);
 849         return ERR_PTR(error);
 850 }
 851
 852 static int __init init_hugetlbfs_fs(void)
 853 {
 854         int error;
 855         struct vfsmount *vfsmount;
 856
 857         hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
 858                                         sizeof(struct hugetlbfs_inode_info),
 859                                         0, 0, init_once, NULL);
 860         if (hugetlbfs_inode_cachep == NULL)
 861                 return -ENOMEM;
 862
 863         error = register_filesystem(&hugetlbfs_fs_type);
 864         if (error)
 865                 goto out;
 866
 867         vfsmount = kern_mount(&hugetlbfs_fs_type);
 868
 869         if (!IS_ERR(vfsmount)) {
 870                 hugetlbfs_vfsmount = vfsmount;
 871                 return 0;
 872         }
 873
 874         error = PTR_ERR(vfsmount);
 875
 876  out:
 877         if (error)
 878                 kmem_cache_destroy(hugetlbfs_inode_cachep);
 879         return error;
 880 }
 881
 882 static void __exit exit_hugetlbfs_fs(void)
 883 {
 884         kmem_cache_destroy(hugetlbfs_inode_cachep);
 885         unregister_filesystem(&hugetlbfs_fs_type);
 886 }
 887
 888 module_init(init_hugetlbfs_fs)
 889 module_exit(exit_hugetlbfs_fs)
 890
 891 MODULE_LICENSE("GPL");