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