fs/hugetlbfs/inode.c

   1 /*
   2  * hugetlbpage-backed filesystem.  Based on ramfs.
   3  *
   4  * William Irwin, 2002
   5  *
   6  * Copyright (C) 2002 Linus Torvalds.
   7  */
   8
   9 #include <linux/module.h>
  10 #include <linux/thread_info.h>
  11 #include <asm/current.h>
  12 #include <linux/sched.h>                /* remove ASAP */
  13 #include <linux/fs.h>
  14 #include <linux/mount.h>
  15 #include <linux/file.h>
  16 #include <linux/kernel.h>
  17 #include <linux/writeback.h>
  18 #include <linux/pagemap.h>
  19 #include <linux/highmem.h>
  20 #include <linux/init.h>
  21 #include <linux/string.h>
  22 #include <linux/capability.h>
  23 #include <linux/ctype.h>
  24 #include <linux/backing-dev.h>
  25 #include <linux/hugetlb.h>
  26 #include <linux/pagevec.h>
  27 #include <linux/parser.h>
  28 #include <linux/mman.h>
  29 #include <linux/quotaops.h>
  30 #include <linux/slab.h>
  31 #include <linux/dnotify.h>
  32 #include <linux/statfs.h>
  33 #include <linux/security.h>
  34
  35 #include <asm/uaccess.h>
  36
  37 /* some random number */
  38 #define HUGETLBFS_MAGIC 0x958458f6
  39
  40 static const struct super_operations hugetlbfs_ops;
  41 static const struct address_space_operations hugetlbfs_aops;
  42 const struct file_operations hugetlbfs_file_operations;
  43 static const struct inode_operations hugetlbfs_dir_inode_operations;
  44 static const struct inode_operations hugetlbfs_inode_operations;
  45
  46 static struct backing_dev_info hugetlbfs_backing_dev_info = {
  47         .ra_pages       = 0,    /* No readahead */
  48         .capabilities   = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
  49 };
  50
  51 int sysctl_hugetlb_shm_group;
  52
  53 enum {
  54         Opt_size, Opt_nr_inodes,
  55         Opt_mode, Opt_uid, Opt_gid,
  56         Opt_err,
  57 };
  58
  59 static match_table_t tokens = {
  60         {Opt_size,      "size=%s"},
  61         {Opt_nr_inodes, "nr_inodes=%s"},
  62         {Opt_mode,      "mode=%o"},
  63         {Opt_uid,       "uid=%u"},
  64         {Opt_gid,       "gid=%u"},
  65         {Opt_err,       NULL},
  66 };
  67
  68 static void huge_pagevec_release(struct pagevec *pvec)
  69 {
  70         int i;
  71
  72         for (i = 0; i < pagevec_count(pvec); ++i)
  73                 put_page(pvec->pages[i]);
  74
  75         pagevec_reinit(pvec);
  76 }
  77
  78 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
  79 {
  80         struct inode *inode = file->f_path.dentry->d_inode;
  81         loff_t len, vma_len;
  82         int ret;
  83
  84         /*
  85          * vma alignment has already been checked by prepare_hugepage_range.
  86          * If you add any error returns here, do so after setting VM_HUGETLB,
  87          * so is_vm_hugetlb_page tests below unmap_region go the right way
  88          * when do_mmap_pgoff unwinds (may be important on powerpc and ia64).
  89          */
  90         vma->vm_flags |= VM_HUGETLB | VM_RESERVED;
  91         vma->vm_ops = &hugetlb_vm_ops;
  92
  93         vma_len = (loff_t)(vma->vm_end - vma->vm_start);
  94
  95         mutex_lock(&inode->i_mutex);
  96         file_accessed(file);
  97
  98         ret = -ENOMEM;
  99         len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
 100
 101         if (vma->vm_flags & VM_MAYSHARE &&
 102             hugetlb_reserve_pages(inode, vma->vm_pgoff >> (HPAGE_SHIFT-PAGE_SHIFT),
 103                                   len >> HPAGE_SHIFT))
 104                 goto out;
 105
 106         ret = 0;
 107         hugetlb_prefault_arch_hook(vma->vm_mm);
 108         if (vma->vm_flags & VM_WRITE && inode->i_size < len)
 109                 inode->i_size = len;
 110 out:
 111         mutex_unlock(&inode->i_mutex);
 112
 113         return ret;
 114 }
 115
 116 /*
 117  * Called under down_write(mmap_sem).
 118  */
 119
 120 #ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
 121 static unsigned long
 122 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 123                 unsigned long len, unsigned long pgoff, unsigned long flags)
 124 {
 125         struct mm_struct *mm = current->mm;
 126         struct vm_area_struct *vma;
 127         unsigned long start_addr;
 128
 129         if (len & ~HPAGE_MASK)
 130                 return -EINVAL;
 131         if (len > TASK_SIZE)
 132                 return -ENOMEM;
 133
 134         if (flags & MAP_FIXED) {
 135                 if (prepare_hugepage_range(addr, len, pgoff))
 136                         return -EINVAL;
 137                 return addr;
 138         }
 139
 140         if (addr) {
 141                 addr = ALIGN(addr, HPAGE_SIZE);
 142                 vma = find_vma(mm, addr);
 143                 if (TASK_SIZE - len >= addr &&
 144                     (!vma || addr + len <= vma->vm_start))
 145                         return addr;
 146         }
 147
 148         start_addr = mm->free_area_cache;
 149
 150         if (len <= mm->cached_hole_size)
 151                 start_addr = TASK_UNMAPPED_BASE;
 152
 153 full_search:
 154         addr = ALIGN(start_addr, HPAGE_SIZE);
 155
 156         for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
 157                 /* At this point:  (!vma || addr < vma->vm_end). */
 158                 if (TASK_SIZE - len < addr) {
 159                         /*
 160                          * Start a new search - just in case we missed
 161                          * some holes.
 162                          */
 163                         if (start_addr != TASK_UNMAPPED_BASE) {
 164                                 start_addr = TASK_UNMAPPED_BASE;
 165                                 goto full_search;
 166                         }
 167                         return -ENOMEM;
 168                 }
 169
 170                 if (!vma || addr + len <= vma->vm_start)
 171                         return addr;
 172                 addr = ALIGN(vma->vm_end, HPAGE_SIZE);
 173         }
 174 }
 175 #endif
 176
 177 /*
 178  * Read a page. Again trivial. If it didn't already exist
 179  * in the page cache, it is zero-filled.
 180  */
 181 static int hugetlbfs_readpage(struct file *file, struct page * page)
 182 {
 183         unlock_page(page);
 184         return -EINVAL;
 185 }
 186
 187 static int hugetlbfs_prepare_write(struct file *file,
 188                         struct page *page, unsigned offset, unsigned to)
 189 {
 190         return -EINVAL;
 191 }
 192
 193 static int hugetlbfs_commit_write(struct file *file,
 194                         struct page *page, unsigned offset, unsigned to)
 195 {
 196         return -EINVAL;
 197 }
 198
 199 static void truncate_huge_page(struct page *page)
 200 {
 201         cancel_dirty_page(page, /* No IO accounting for huge pages? */0);
 202         ClearPageUptodate(page);
 203         remove_from_page_cache(page);
 204         put_page(page);
 205 }
 206
 207 static void truncate_hugepages(struct inode *inode, loff_t lstart)
 208 {
 209         struct address_space *mapping = &inode->i_data;
 210         const pgoff_t start = lstart >> HPAGE_SHIFT;
 211         struct pagevec pvec;
 212         pgoff_t next;
 213         int i, freed = 0;
 214
 215         pagevec_init(&pvec, 0);
 216         next = start;
 217         while (1) {
 218                 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
 219                         if (next == start)
 220                                 break;
 221                         next = start;
 222                         continue;
 223                 }
 224
 225                 for (i = 0; i < pagevec_count(&pvec); ++i) {
 226                         struct page *page = pvec.pages[i];
 227
 228                         lock_page(page);
 229                         if (page->index > next)
 230                                 next = page->index;
 231                         ++next;
 232                         truncate_huge_page(page);
 233                         unlock_page(page);
 234                         hugetlb_put_quota(mapping);
 235                         freed++;
 236                 }
 237                 huge_pagevec_release(&pvec);
 238         }
 239         BUG_ON(!lstart && mapping->nrpages);
 240         hugetlb_unreserve_pages(inode, start, freed);
 241 }
 242
 243 static void hugetlbfs_delete_inode(struct inode *inode)
 244 {
 245         truncate_hugepages(inode, 0);
 246         clear_inode(inode);
 247 }
 248
 249 static void hugetlbfs_forget_inode(struct inode *inode) __releases(inode_lock)
 250 {
 251         struct super_block *sb = inode->i_sb;
 252
 253         if (!hlist_unhashed(&inode->i_hash)) {
 254                 if (!(inode->i_state & (I_DIRTY|I_LOCK)))
 255                         list_move(&inode->i_list, &inode_unused);
 256                 inodes_stat.nr_unused++;
 257                 if (!sb || (sb->s_flags & MS_ACTIVE)) {
 258                         spin_unlock(&inode_lock);
 259                         return;
 260                 }
 261                 inode->i_state |= I_WILL_FREE;
 262                 spin_unlock(&inode_lock);
 263                 /*
 264                  * write_inode_now is a noop as we set BDI_CAP_NO_WRITEBACK
 265                  * in our backing_dev_info.
 266                  */
 267                 write_inode_now(inode, 1);
 268                 spin_lock(&inode_lock);
 269                 inode->i_state &= ~I_WILL_FREE;
 270                 inodes_stat.nr_unused--;
 271                 hlist_del_init(&inode->i_hash);
 272         }
 273         list_del_init(&inode->i_list);
 274         list_del_init(&inode->i_sb_list);
 275         inode->i_state |= I_FREEING;
 276         inodes_stat.nr_inodes--;
 277         spin_unlock(&inode_lock);
 278         truncate_hugepages(inode, 0);
 279         clear_inode(inode);
 280         destroy_inode(inode);
 281 }
 282
 283 static void hugetlbfs_drop_inode(struct inode *inode)
 284 {
 285         if (!inode->i_nlink)
 286                 generic_delete_inode(inode);
 287         else
 288                 hugetlbfs_forget_inode(inode);
 289 }
 290
 291 static inline void
 292 hugetlb_vmtruncate_list(struct prio_tree_root *root, pgoff_t pgoff)
 293 {
 294         struct vm_area_struct *vma;
 295         struct prio_tree_iter iter;
 296
 297         vma_prio_tree_foreach(vma, &iter, root, pgoff, ULONG_MAX) {
 298                 unsigned long v_offset;
 299
 300                 /*
 301                  * Can the expression below overflow on 32-bit arches?
 302                  * No, because the prio_tree returns us only those vmas
 303                  * which overlap the truncated area starting at pgoff,
 304                  * and no vma on a 32-bit arch can span beyond the 4GB.
 305                  */
 306                 if (vma->vm_pgoff < pgoff)
 307                         v_offset = (pgoff - vma->vm_pgoff) << PAGE_SHIFT;
 308                 else
 309                         v_offset = 0;
 310
 311                 __unmap_hugepage_range(vma,
 312                                 vma->vm_start + v_offset, vma->vm_end);
 313         }
 314 }
 315
 316 /*
 317  * Expanding truncates are not allowed.
 318  */
 319 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
 320 {
 321         pgoff_t pgoff;
 322         struct address_space *mapping = inode->i_mapping;
 323
 324         if (offset > inode->i_size)
 325                 return -EINVAL;
 326
 327         BUG_ON(offset & ~HPAGE_MASK);
 328         pgoff = offset >> PAGE_SHIFT;
 329
 330         inode->i_size = offset;
 331         spin_lock(&mapping->i_mmap_lock);
 332         if (!prio_tree_empty(&mapping->i_mmap))
 333                 hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff);
 334         spin_unlock(&mapping->i_mmap_lock);
 335         truncate_hugepages(inode, offset);
 336         return 0;
 337 }
 338
 339 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
 340 {
 341         struct inode *inode = dentry->d_inode;
 342         int error;
 343         unsigned int ia_valid = attr->ia_valid;
 344
 345         BUG_ON(!inode);
 346
 347         error = inode_change_ok(inode, attr);
 348         if (error)
 349                 goto out;
 350
 351         if (ia_valid & ATTR_SIZE) {
 352                 error = -EINVAL;
 353                 if (!(attr->ia_size & ~HPAGE_MASK))
 354                         error = hugetlb_vmtruncate(inode, attr->ia_size);
 355                 if (error)
 356                         goto out;
 357                 attr->ia_valid &= ~ATTR_SIZE;
 358         }
 359         error = inode_setattr(inode, attr);
 360 out:
 361         return error;
 362 }
 363
 364 static struct inode *hugetlbfs_get_inode(struct super_block *sb, uid_t uid,
 365                                         gid_t gid, int mode, dev_t dev)
 366 {
 367         struct inode *inode;
 368
 369         inode = new_inode(sb);
 370         if (inode) {
 371                 struct hugetlbfs_inode_info *info;
 372                 inode->i_mode = mode;
 373                 inode->i_uid = uid;
 374                 inode->i_gid = gid;
 375                 inode->i_blocks = 0;
 376                 inode->i_mapping->a_ops = &hugetlbfs_aops;
 377                 inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info;
 378                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 379                 INIT_LIST_HEAD(&inode->i_mapping->private_list);
 380                 info = HUGETLBFS_I(inode);
 381                 mpol_shared_policy_init(&info->policy, MPOL_DEFAULT, NULL);
 382                 switch (mode & S_IFMT) {
 383                 default:
 384                         init_special_inode(inode, mode, dev);
 385                         break;
 386                 case S_IFREG:
 387                         inode->i_op = &hugetlbfs_inode_operations;
 388                         inode->i_fop = &hugetlbfs_file_operations;
 389                         break;
 390                 case S_IFDIR:
 391                         inode->i_op = &hugetlbfs_dir_inode_operations;
 392                         inode->i_fop = &simple_dir_operations;
 393
 394                         /* directory inodes start off with i_nlink == 2 (for "." entry) */
 395                         inc_nlink(inode);
 396                         break;
 397                 case S_IFLNK:
 398                         inode->i_op = &page_symlink_inode_operations;
 399                         break;
 400                 }
 401         }
 402         return inode;
 403 }
 404
 405 /*
 406  * File creation. Allocate an inode, and we're done..
 407  */
 408 static int hugetlbfs_mknod(struct inode *dir,
 409                         struct dentry *dentry, int mode, dev_t dev)
 410 {
 411         struct inode *inode;
 412         int error = -ENOSPC;
 413         gid_t gid;
 414
 415         if (dir->i_mode & S_ISGID) {
 416                 gid = dir->i_gid;
 417                 if (S_ISDIR(mode))
 418                         mode |= S_ISGID;
 419         } else {
 420                 gid = current->fsgid;
 421         }
 422         inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid, gid, mode, dev);
 423         if (inode) {
 424                 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 425                 d_instantiate(dentry, inode);
 426                 dget(dentry);   /* Extra count - pin the dentry in core */
 427                 error = 0;
 428         }
 429         return error;
 430 }
 431
 432 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 433 {
 434         int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
 435         if (!retval)
 436                 inc_nlink(dir);
 437         return retval;
 438 }
 439
 440 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, int mode, struct nameidata *nd)
 441 {
 442         return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
 443 }
 444
 445 static int hugetlbfs_symlink(struct inode *dir,
 446                         struct dentry *dentry, const char *symname)
 447 {
 448         struct inode *inode;
 449         int error = -ENOSPC;
 450         gid_t gid;
 451
 452         if (dir->i_mode & S_ISGID)
 453                 gid = dir->i_gid;
 454         else
 455                 gid = current->fsgid;
 456
 457         inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid,
 458                                         gid, S_IFLNK|S_IRWXUGO, 0);
 459         if (inode) {
 460                 int l = strlen(symname)+1;
 461                 error = page_symlink(inode, symname, l);
 462                 if (!error) {
 463                         d_instantiate(dentry, inode);
 464                         dget(dentry);
 465                 } else
 466                         iput(inode);
 467         }
 468         dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 469
 470         return error;
 471 }
 472
 473 /*
 474  * mark the head page dirty
 475  */
 476 static int hugetlbfs_set_page_dirty(struct page *page)
 477 {
 478         struct page *head = compound_head(page);
 479
 480         SetPageDirty(head);
 481         return 0;
 482 }
 483
 484 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 485 {
 486         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
 487
 488         buf->f_type = HUGETLBFS_MAGIC;
 489         buf->f_bsize = HPAGE_SIZE;
 490         if (sbinfo) {
 491                 spin_lock(&sbinfo->stat_lock);
 492                 /* If no limits set, just report 0 for max/free/used
 493                  * blocks, like simple_statfs() */
 494                 if (sbinfo->max_blocks >= 0) {
 495                         buf->f_blocks = sbinfo->max_blocks;
 496                         buf->f_bavail = buf->f_bfree = sbinfo->free_blocks;
 497                         buf->f_files = sbinfo->max_inodes;
 498                         buf->f_ffree = sbinfo->free_inodes;
 499                 }
 500                 spin_unlock(&sbinfo->stat_lock);
 501         }
 502         buf->f_namelen = NAME_MAX;
 503         return 0;
 504 }
 505
 506 static void hugetlbfs_put_super(struct super_block *sb)
 507 {
 508         struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
 509
 510         if (sbi) {
 511                 sb->s_fs_info = NULL;
 512                 kfree(sbi);
 513         }
 514 }
 515
 516 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
 517 {
 518         if (sbinfo->free_inodes >= 0) {
 519                 spin_lock(&sbinfo->stat_lock);
 520                 if (unlikely(!sbinfo->free_inodes)) {
 521                         spin_unlock(&sbinfo->stat_lock);
 522                         return 0;
 523                 }
 524                 sbinfo->free_inodes--;
 525                 spin_unlock(&sbinfo->stat_lock);
 526         }
 527
 528         return 1;
 529 }
 530
 531 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
 532 {
 533         if (sbinfo->free_inodes >= 0) {
 534                 spin_lock(&sbinfo->stat_lock);
 535                 sbinfo->free_inodes++;
 536                 spin_unlock(&sbinfo->stat_lock);
 537         }
 538 }
 539
 540
 541 static struct kmem_cache *hugetlbfs_inode_cachep;
 542
 543 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
 544 {
 545         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
 546         struct hugetlbfs_inode_info *p;
 547
 548         if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
 549                 return NULL;
 550         p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL);
 551         if (unlikely(!p)) {
 552                 hugetlbfs_inc_free_inodes(sbinfo);
 553                 return NULL;
 554         }
 555         return &p->vfs_inode;
 556 }
 557
 558 static void hugetlbfs_destroy_inode(struct inode *inode)
 559 {
 560         hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
 561         mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
 562         kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
 563 }
 564
 565 static const struct address_space_operations hugetlbfs_aops = {
 566         .readpage       = hugetlbfs_readpage,
 567         .prepare_write  = hugetlbfs_prepare_write,
 568         .commit_write   = hugetlbfs_commit_write,
 569         .set_page_dirty = hugetlbfs_set_page_dirty,
 570 };
 571
 572
 573 static void init_once(void *foo, struct kmem_cache *cachep, unsigned long flags)
 574 {
 575         struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
 576
 577         inode_init_once(&ei->vfs_inode);
 578 }
 579
 580 const struct file_operations hugetlbfs_file_operations = {
 581         .mmap                   = hugetlbfs_file_mmap,
 582         .fsync                  = simple_sync_file,
 583         .get_unmapped_area      = hugetlb_get_unmapped_area,
 584 };
 585
 586 static const struct inode_operations hugetlbfs_dir_inode_operations = {
 587         .create         = hugetlbfs_create,
 588         .lookup         = simple_lookup,
 589         .link           = simple_link,
 590         .unlink         = simple_unlink,
 591         .symlink        = hugetlbfs_symlink,
 592         .mkdir          = hugetlbfs_mkdir,
 593         .rmdir          = simple_rmdir,
 594         .mknod          = hugetlbfs_mknod,
 595         .rename         = simple_rename,
 596         .setattr        = hugetlbfs_setattr,
 597 };
 598
 599 static const struct inode_operations hugetlbfs_inode_operations = {
 600         .setattr        = hugetlbfs_setattr,
 601 };
 602
 603 static const struct super_operations hugetlbfs_ops = {
 604         .alloc_inode    = hugetlbfs_alloc_inode,
 605         .destroy_inode  = hugetlbfs_destroy_inode,
 606         .statfs         = hugetlbfs_statfs,
 607         .delete_inode   = hugetlbfs_delete_inode,
 608         .drop_inode     = hugetlbfs_drop_inode,
 609         .put_super      = hugetlbfs_put_super,
 610 };
 611
 612 static int
 613 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
 614 {
 615         char *p, *rest;
 616         substring_t args[MAX_OPT_ARGS];
 617         int option;
 618
 619         if (!options)
 620                 return 0;
 621
 622         while ((p = strsep(&options, ",")) != NULL) {
 623                 int token;
 624                 if (!*p)
 625                         continue;
 626
 627                 token = match_token(p, tokens, args);
 628                 switch (token) {
 629                 case Opt_uid:
 630                         if (match_int(&args[0], &option))
 631                                 goto bad_val;
 632                         pconfig->uid = option;
 633                         break;
 634
 635                 case Opt_gid:
 636                         if (match_int(&args[0], &option))
 637                                 goto bad_val;
 638                         pconfig->gid = option;
 639                         break;
 640
 641                 case Opt_mode:
 642                         if (match_octal(&args[0], &option))
 643                                 goto bad_val;
 644                         pconfig->mode = option & 0777U;
 645                         break;
 646
 647                 case Opt_size: {
 648                         unsigned long long size;
 649                         /* memparse() will accept a K/M/G without a digit */
 650                         if (!isdigit(*args[0].from))
 651                                 goto bad_val;
 652                         size = memparse(args[0].from, &rest);
 653                         if (*rest == '%') {
 654                                 size <<= HPAGE_SHIFT;
 655                                 size *= max_huge_pages;
 656                                 do_div(size, 100);
 657                         }
 658                         pconfig->nr_blocks = (size >> HPAGE_SHIFT);
 659                         break;
 660                 }
 661
 662                 case Opt_nr_inodes:
 663                         /* memparse() will accept a K/M/G without a digit */
 664                         if (!isdigit(*args[0].from))
 665                                 goto bad_val;
 666                         pconfig->nr_inodes = memparse(args[0].from, &rest);
 667                         break;
 668
 669                 default:
 670                         printk(KERN_ERR "hugetlbfs: Bad mount option: \"%s\"\n",
 671                                  p);
 672                         return -EINVAL;
 673                         break;
 674                 }
 675         }
 676         return 0;
 677
 678 bad_val:
 679         printk(KERN_ERR "hugetlbfs: Bad value '%s' for mount option '%s'\n",
 680                args[0].from, p);
 681         return 1;
 682 }
 683
 684 static int
 685 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
 686 {
 687         struct inode * inode;
 688         struct dentry * root;
 689         int ret;
 690         struct hugetlbfs_config config;
 691         struct hugetlbfs_sb_info *sbinfo;
 692
 693         config.nr_blocks = -1; /* No limit on size by default */
 694         config.nr_inodes = -1; /* No limit on number of inodes by default */
 695         config.uid = current->fsuid;
 696         config.gid = current->fsgid;
 697         config.mode = 0755;
 698         ret = hugetlbfs_parse_options(data, &config);
 699         if (ret)
 700                 return ret;
 701
 702         sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
 703         if (!sbinfo)
 704                 return -ENOMEM;
 705         sb->s_fs_info = sbinfo;
 706         spin_lock_init(&sbinfo->stat_lock);
 707         sbinfo->max_blocks = config.nr_blocks;
 708         sbinfo->free_blocks = config.nr_blocks;
 709         sbinfo->max_inodes = config.nr_inodes;
 710         sbinfo->free_inodes = config.nr_inodes;
 711         sb->s_maxbytes = MAX_LFS_FILESIZE;
 712         sb->s_blocksize = HPAGE_SIZE;
 713         sb->s_blocksize_bits = HPAGE_SHIFT;
 714         sb->s_magic = HUGETLBFS_MAGIC;
 715         sb->s_op = &hugetlbfs_ops;
 716         sb->s_time_gran = 1;
 717         inode = hugetlbfs_get_inode(sb, config.uid, config.gid,
 718                                         S_IFDIR | config.mode, 0);
 719         if (!inode)
 720                 goto out_free;
 721
 722         root = d_alloc_root(inode);
 723         if (!root) {
 724                 iput(inode);
 725                 goto out_free;
 726         }
 727         sb->s_root = root;
 728         return 0;
 729 out_free:
 730         kfree(sbinfo);
 731         return -ENOMEM;
 732 }
 733
 734 int hugetlb_get_quota(struct address_space *mapping)
 735 {
 736         int ret = 0;
 737         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
 738
 739         if (sbinfo->free_blocks > -1) {
 740                 spin_lock(&sbinfo->stat_lock);
 741                 if (sbinfo->free_blocks > 0)
 742                         sbinfo->free_blocks--;
 743                 else
 744                         ret = -ENOMEM;
 745                 spin_unlock(&sbinfo->stat_lock);
 746         }
 747
 748         return ret;
 749 }
 750
 751 void hugetlb_put_quota(struct address_space *mapping)
 752 {
 753         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
 754
 755         if (sbinfo->free_blocks > -1) {
 756                 spin_lock(&sbinfo->stat_lock);
 757                 sbinfo->free_blocks++;
 758                 spin_unlock(&sbinfo->stat_lock);
 759         }
 760 }
 761
 762 static int hugetlbfs_get_sb(struct file_system_type *fs_type,
 763         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
 764 {
 765         return get_sb_nodev(fs_type, flags, data, hugetlbfs_fill_super, mnt);
 766 }
 767
 768 static struct file_system_type hugetlbfs_fs_type = {
 769         .name           = "hugetlbfs",
 770         .get_sb         = hugetlbfs_get_sb,
 771         .kill_sb        = kill_litter_super,
 772 };
 773
 774 static struct vfsmount *hugetlbfs_vfsmount;
 775
 776 static int can_do_hugetlb_shm(void)
 777 {
 778         return likely(capable(CAP_IPC_LOCK) ||
 779                         in_group_p(sysctl_hugetlb_shm_group) ||
 780                         can_do_mlock());
 781 }
 782
 783 struct file *hugetlb_file_setup(const char *name, size_t size)
 784 {
 785         int error = -ENOMEM;
 786         struct file *file;
 787         struct inode *inode;
 788         struct dentry *dentry, *root;
 789         struct qstr quick_string;
 790
 791         if (!hugetlbfs_vfsmount)
 792                 return ERR_PTR(-ENOENT);
 793
 794         if (!can_do_hugetlb_shm())
 795                 return ERR_PTR(-EPERM);
 796
 797         if (!user_shm_lock(size, current->user))
 798                 return ERR_PTR(-ENOMEM);
 799
 800         root = hugetlbfs_vfsmount->mnt_root;
 801         quick_string.name = name;
 802         quick_string.len = strlen(quick_string.name);
 803         quick_string.hash = 0;
 804         dentry = d_alloc(root, &quick_string);
 805         if (!dentry)
 806                 goto out_shm_unlock;
 807
 808         error = -ENFILE;
 809         file = get_empty_filp();
 810         if (!file)
 811                 goto out_dentry;
 812
 813         error = -ENOSPC;
 814         inode = hugetlbfs_get_inode(root->d_sb, current->fsuid,
 815                                 current->fsgid, S_IFREG | S_IRWXUGO, 0);
 816         if (!inode)
 817                 goto out_file;
 818
 819         error = -ENOMEM;
 820         if (hugetlb_reserve_pages(inode, 0, size >> HPAGE_SHIFT))
 821                 goto out_inode;
 822
 823         d_instantiate(dentry, inode);
 824         inode->i_size = size;
 825         inode->i_nlink = 0;
 826         file->f_path.mnt = mntget(hugetlbfs_vfsmount);
 827         file->f_path.dentry = dentry;
 828         file->f_mapping = inode->i_mapping;
 829         file->f_op = &hugetlbfs_file_operations;
 830         file->f_mode = FMODE_WRITE | FMODE_READ;
 831         return file;
 832
 833 out_inode:
 834         iput(inode);
 835 out_file:
 836         put_filp(file);
 837 out_dentry:
 838         dput(dentry);
 839 out_shm_unlock:
 840         user_shm_unlock(size, current->user);
 841         return ERR_PTR(error);
 842 }
 843
 844 static int __init init_hugetlbfs_fs(void)
 845 {
 846         int error;
 847         struct vfsmount *vfsmount;
 848
 849         hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
 850                                         sizeof(struct hugetlbfs_inode_info),
 851                                         0, 0, init_once);
 852         if (hugetlbfs_inode_cachep == NULL)
 853                 return -ENOMEM;
 854
 855         error = register_filesystem(&hugetlbfs_fs_type);
 856         if (error)
 857                 goto out;
 858
 859         vfsmount = kern_mount(&hugetlbfs_fs_type);
 860
 861         if (!IS_ERR(vfsmount)) {
 862                 hugetlbfs_vfsmount = vfsmount;
 863                 return 0;
 864         }
 865
 866         error = PTR_ERR(vfsmount);
 867
 868  out:
 869         if (error)
 870                 kmem_cache_destroy(hugetlbfs_inode_cachep);
 871         return error;
 872 }
 873
 874 static void __exit exit_hugetlbfs_fs(void)
 875 {
 876         kmem_cache_destroy(hugetlbfs_inode_cachep);
 877         unregister_filesystem(&hugetlbfs_fs_type);
 878 }
 879
 880 module_init(init_hugetlbfs_fs)
 881 module_exit(exit_hugetlbfs_fs)
 882
 883 MODULE_LICENSE("GPL");