err.no Git - linux-2.6/blob - fs/hugetlbfs/inode.c

   1 /*
   2  * hugetlbpage-backed filesystem.  Based on ramfs.
   3  *
   4  * William Irwin, 2002
   5  *
   6  * Copyright (C) 2002 Linus Torvalds.
   7  */
   8
   9 #include <linux/module.h>
  10 #include <linux/thread_info.h>
  11 #include <asm/current.h>
  12 #include <linux/sched.h>                /* remove ASAP */
  13 #include <linux/fs.h>
  14 #include <linux/mount.h>
  15 #include <linux/file.h>
  16 #include <linux/writeback.h>
  17 #include <linux/pagemap.h>
  18 #include <linux/highmem.h>
  19 #include <linux/init.h>
  20 #include <linux/string.h>
  21 #include <linux/backing-dev.h>
  22 #include <linux/hugetlb.h>
  23 #include <linux/pagevec.h>
  24 #include <linux/quotaops.h>
  25 #include <linux/slab.h>
  26 #include <linux/dnotify.h>
  27 #include <linux/statfs.h>
  28 #include <linux/security.h>
  29
  30 #include <asm/uaccess.h>
  31
  32 /* some random number */
  33 #define HUGETLBFS_MAGIC 0x958458f6
  34
  35 static struct super_operations hugetlbfs_ops;
  36 static struct address_space_operations hugetlbfs_aops;
  37 struct file_operations hugetlbfs_file_operations;
  38 static struct inode_operations hugetlbfs_dir_inode_operations;
  39 static struct inode_operations hugetlbfs_inode_operations;
  40
  41 static struct backing_dev_info hugetlbfs_backing_dev_info = {
  42         .ra_pages       = 0,    /* No readahead */
  43         .capabilities   = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
  44 };
  45
  46 int sysctl_hugetlb_shm_group;
  47
  48 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
  49 {
  50         struct inode *inode = file->f_dentry->d_inode;
  51         struct address_space *mapping = inode->i_mapping;
  52         loff_t len, vma_len;
  53         int ret;
  54
  55         if ((vma->vm_flags & (VM_MAYSHARE | VM_WRITE)) == VM_WRITE)
  56                 return -EINVAL;
  57
  58         if (vma->vm_pgoff & (HPAGE_SIZE / PAGE_SIZE - 1))
  59                 return -EINVAL;
  60
  61         if (vma->vm_start & ~HPAGE_MASK)
  62                 return -EINVAL;
  63
  64         if (vma->vm_end & ~HPAGE_MASK)
  65                 return -EINVAL;
  66
  67         if (vma->vm_end - vma->vm_start < HPAGE_SIZE)
  68                 return -EINVAL;
  69
  70         vma_len = (loff_t)(vma->vm_end - vma->vm_start);
  71
  72         down(&inode->i_sem);
  73         file_accessed(file);
  74         vma->vm_flags |= VM_HUGETLB | VM_RESERVED;
  75         vma->vm_ops = &hugetlb_vm_ops;
  76
  77         ret = -ENOMEM;
  78         len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
  79         if (!(vma->vm_flags & VM_WRITE) && len > inode->i_size)
  80                 goto out;
  81
  82         ret = hugetlb_prefault(mapping, vma);
  83         if (ret)
  84                 goto out;
  85
  86         if (inode->i_size < len)
  87                 inode->i_size = len;
  88 out:
  89         up(&inode->i_sem);
  90
  91         return ret;
  92 }
  93
  94 /*
  95  * Called under down_write(mmap_sem).
  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         if (inode->i_data.nrpages)
 228                 truncate_hugepages(&inode->i_data, 0);
 229         clear_inode(inode);
 230 }
 231
 232 static void hugetlbfs_do_delete_inode(struct inode *inode)
 233 {
 234         struct super_operations *op = inode->i_sb->s_op;
 235
 236         list_del_init(&inode->i_list);
 237         list_del_init(&inode->i_sb_list);
 238         inode->i_state |= I_FREEING;
 239         inodes_stat.nr_inodes--;
 240         spin_unlock(&inode_lock);
 241
 242         security_inode_delete(inode);
 243
 244         if (op->delete_inode) {
 245                 void (*delete)(struct inode *) = op->delete_inode;
 246                 if (!is_bad_inode(inode))
 247                         DQUOT_INIT(inode);
 248                 /* Filesystems implementing their own
 249                  * s_op->delete_inode are required to call
 250                  * truncate_inode_pages and clear_inode()
 251                  * internally
 252                  */
 253                 delete(inode);
 254         } else {
 255                 truncate_inode_pages(&inode->i_data, 0);
 256                 clear_inode(inode);
 257         }
 258
 259         spin_lock(&inode_lock);
 260         hlist_del_init(&inode->i_hash);
 261         spin_unlock(&inode_lock);
 262         wake_up_inode(inode);
 263         if (inode->i_state != I_CLEAR)
 264                 BUG();
 265         destroy_inode(inode);
 266 }
 267
 268 static void hugetlbfs_forget_inode(struct inode *inode)
 269 {
 270         struct super_block *super_block = inode->i_sb;
 271
 272         if (hlist_unhashed(&inode->i_hash))
 273                 goto out_truncate;
 274
 275         if (!(inode->i_state & (I_DIRTY|I_LOCK))) {
 276                 list_del(&inode->i_list);
 277                 list_add(&inode->i_list, &inode_unused);
 278         }
 279         inodes_stat.nr_unused++;
 280         if (!super_block || (super_block->s_flags & MS_ACTIVE)) {
 281                 spin_unlock(&inode_lock);
 282                 return;
 283         }
 284
 285         /* write_inode_now() ? */
 286         inodes_stat.nr_unused--;
 287         hlist_del_init(&inode->i_hash);
 288 out_truncate:
 289         list_del_init(&inode->i_list);
 290         list_del_init(&inode->i_sb_list);
 291         inode->i_state |= I_FREEING;
 292         inodes_stat.nr_inodes--;
 293         spin_unlock(&inode_lock);
 294         if (inode->i_data.nrpages)
 295                 truncate_hugepages(&inode->i_data, 0);
 296
 297         clear_inode(inode);
 298         destroy_inode(inode);
 299 }
 300
 301 static void hugetlbfs_drop_inode(struct inode *inode)
 302 {
 303         if (!inode->i_nlink)
 304                 hugetlbfs_do_delete_inode(inode);
 305         else
 306                 hugetlbfs_forget_inode(inode);
 307 }
 308
 309 /*
 310  * h_pgoff is in HPAGE_SIZE units.
 311  * vma->vm_pgoff is in PAGE_SIZE units.
 312  */
 313 static inline void
 314 hugetlb_vmtruncate_list(struct prio_tree_root *root, unsigned long h_pgoff)
 315 {
 316         struct vm_area_struct *vma;
 317         struct prio_tree_iter iter;
 318
 319         vma_prio_tree_foreach(vma, &iter, root, h_pgoff, ULONG_MAX) {
 320                 unsigned long h_vm_pgoff;
 321                 unsigned long v_offset;
 322
 323                 h_vm_pgoff = vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT);
 324                 v_offset = (h_pgoff - h_vm_pgoff) << HPAGE_SHIFT;
 325                 /*
 326                  * Is this VMA fully outside the truncation point?
 327                  */
 328                 if (h_vm_pgoff >= h_pgoff)
 329                         v_offset = 0;
 330
 331                 unmap_hugepage_range(vma,
 332                                 vma->vm_start + v_offset, vma->vm_end);
 333         }
 334 }
 335
 336 /*
 337  * Expanding truncates are not allowed.
 338  */
 339 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
 340 {
 341         unsigned long pgoff;
 342         struct address_space *mapping = inode->i_mapping;
 343
 344         if (offset > inode->i_size)
 345                 return -EINVAL;
 346
 347         BUG_ON(offset & ~HPAGE_MASK);
 348         pgoff = offset >> HPAGE_SHIFT;
 349
 350         inode->i_size = offset;
 351         spin_lock(&mapping->i_mmap_lock);
 352         if (!prio_tree_empty(&mapping->i_mmap))
 353                 hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff);
 354         spin_unlock(&mapping->i_mmap_lock);
 355         truncate_hugepages(mapping, offset);
 356         return 0;
 357 }
 358
 359 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
 360 {
 361         struct inode *inode = dentry->d_inode;
 362         int error;
 363         unsigned int ia_valid = attr->ia_valid;
 364
 365         BUG_ON(!inode);
 366
 367         error = inode_change_ok(inode, attr);
 368         if (error)
 369                 goto out;
 370
 371         if (ia_valid & ATTR_SIZE) {
 372                 error = -EINVAL;
 373                 if (!(attr->ia_size & ~HPAGE_MASK))
 374                         error = hugetlb_vmtruncate(inode, attr->ia_size);
 375                 if (error)
 376                         goto out;
 377                 attr->ia_valid &= ~ATTR_SIZE;
 378         }
 379         error = inode_setattr(inode, attr);
 380 out:
 381         return error;
 382 }
 383
 384 static struct inode *hugetlbfs_get_inode(struct super_block *sb, uid_t uid,
 385                                         gid_t gid, int mode, dev_t dev)
 386 {
 387         struct inode *inode;
 388
 389         inode = new_inode(sb);
 390         if (inode) {
 391                 struct hugetlbfs_inode_info *info;
 392                 inode->i_mode = mode;
 393                 inode->i_uid = uid;
 394                 inode->i_gid = gid;
 395                 inode->i_blksize = HPAGE_SIZE;
 396                 inode->i_blocks = 0;
 397                 inode->i_mapping->a_ops = &hugetlbfs_aops;
 398                 inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info;
 399                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 400                 info = HUGETLBFS_I(inode);
 401                 mpol_shared_policy_init(&info->policy);
 402                 switch (mode & S_IFMT) {
 403                 default:
 404                         init_special_inode(inode, mode, dev);
 405                         break;
 406                 case S_IFREG:
 407                         inode->i_op = &hugetlbfs_inode_operations;
 408                         inode->i_fop = &hugetlbfs_file_operations;
 409                         break;
 410                 case S_IFDIR:
 411                         inode->i_op = &hugetlbfs_dir_inode_operations;
 412                         inode->i_fop = &simple_dir_operations;
 413
 414                         /* directory inodes start off with i_nlink == 2 (for "." entry) */
 415                         inode->i_nlink++;
 416                         break;
 417                 case S_IFLNK:
 418                         inode->i_op = &page_symlink_inode_operations;
 419                         break;
 420                 }
 421         }
 422         return inode;
 423 }
 424
 425 /*
 426  * File creation. Allocate an inode, and we're done..
 427  */
 428 static int hugetlbfs_mknod(struct inode *dir,
 429                         struct dentry *dentry, int mode, dev_t dev)
 430 {
 431         struct inode *inode;
 432         int error = -ENOSPC;
 433         gid_t gid;
 434
 435         if (dir->i_mode & S_ISGID) {
 436                 gid = dir->i_gid;
 437                 if (S_ISDIR(mode))
 438                         mode |= S_ISGID;
 439         } else {
 440                 gid = current->fsgid;
 441         }
 442         inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid, gid, mode, dev);
 443         if (inode) {
 444                 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 445                 d_instantiate(dentry, inode);
 446                 dget(dentry);   /* Extra count - pin the dentry in core */
 447                 error = 0;
 448         }
 449         return error;
 450 }
 451
 452 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 453 {
 454         int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
 455         if (!retval)
 456                 dir->i_nlink++;
 457         return retval;
 458 }
 459
 460 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, int mode, struct nameidata *nd)
 461 {
 462         return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
 463 }
 464
 465 static int hugetlbfs_symlink(struct inode *dir,
 466                         struct dentry *dentry, const char *symname)
 467 {
 468         struct inode *inode;
 469         int error = -ENOSPC;
 470         gid_t gid;
 471
 472         if (dir->i_mode & S_ISGID)
 473                 gid = dir->i_gid;
 474         else
 475                 gid = current->fsgid;
 476
 477         inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid,
 478                                         gid, S_IFLNK|S_IRWXUGO, 0);
 479         if (inode) {
 480                 int l = strlen(symname)+1;
 481                 error = page_symlink(inode, symname, l);
 482                 if (!error) {
 483                         d_instantiate(dentry, inode);
 484                         dget(dentry);
 485                 } else
 486                         iput(inode);
 487         }
 488         dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 489
 490         return error;
 491 }
 492
 493 /*
 494  * For direct-IO reads into hugetlb pages
 495  */
 496 static int hugetlbfs_set_page_dirty(struct page *page)
 497 {
 498         return 0;
 499 }
 500
 501 static int hugetlbfs_statfs(struct super_block *sb, struct kstatfs *buf)
 502 {
 503         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
 504
 505         buf->f_type = HUGETLBFS_MAGIC;
 506         buf->f_bsize = HPAGE_SIZE;
 507         if (sbinfo) {
 508                 spin_lock(&sbinfo->stat_lock);
 509                 buf->f_blocks = sbinfo->max_blocks;
 510                 buf->f_bavail = buf->f_bfree = sbinfo->free_blocks;
 511                 buf->f_files = sbinfo->max_inodes;
 512                 buf->f_ffree = sbinfo->free_inodes;
 513                 spin_unlock(&sbinfo->stat_lock);
 514         }
 515         buf->f_namelen = NAME_MAX;
 516         return 0;
 517 }
 518
 519 static void hugetlbfs_put_super(struct super_block *sb)
 520 {
 521         struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
 522
 523         if (sbi) {
 524                 sb->s_fs_info = NULL;
 525                 kfree(sbi);
 526         }
 527 }
 528
 529 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
 530 {
 531         if (sbinfo->free_inodes >= 0) {
 532                 spin_lock(&sbinfo->stat_lock);
 533                 if (unlikely(!sbinfo->free_inodes)) {
 534                         spin_unlock(&sbinfo->stat_lock);
 535                         return 0;
 536                 }
 537                 sbinfo->free_inodes--;
 538                 spin_unlock(&sbinfo->stat_lock);
 539         }
 540
 541         return 1;
 542 }
 543
 544 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
 545 {
 546         if (sbinfo->free_inodes >= 0) {
 547                 spin_lock(&sbinfo->stat_lock);
 548                 sbinfo->free_inodes++;
 549                 spin_unlock(&sbinfo->stat_lock);
 550         }
 551 }
 552
 553
 554 static kmem_cache_t *hugetlbfs_inode_cachep;
 555
 556 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
 557 {
 558         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
 559         struct hugetlbfs_inode_info *p;
 560
 561         if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
 562                 return NULL;
 563         p = kmem_cache_alloc(hugetlbfs_inode_cachep, SLAB_KERNEL);
 564         if (unlikely(!p)) {
 565                 hugetlbfs_inc_free_inodes(sbinfo);
 566                 return NULL;
 567         }
 568         return &p->vfs_inode;
 569 }
 570
 571 static void hugetlbfs_destroy_inode(struct inode *inode)
 572 {
 573         hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
 574         mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
 575         kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
 576 }
 577
 578 static struct address_space_operations hugetlbfs_aops = {
 579         .readpage       = hugetlbfs_readpage,
 580         .prepare_write  = hugetlbfs_prepare_write,
 581         .commit_write   = hugetlbfs_commit_write,
 582         .set_page_dirty = hugetlbfs_set_page_dirty,
 583 };
 584
 585
 586 static void init_once(void *foo, kmem_cache_t *cachep, unsigned long flags)
 587 {
 588         struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
 589
 590         if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
 591             SLAB_CTOR_CONSTRUCTOR)
 592                 inode_init_once(&ei->vfs_inode);
 593 }
 594
 595 struct file_operations hugetlbfs_file_operations = {
 596         .mmap                   = hugetlbfs_file_mmap,
 597         .fsync                  = simple_sync_file,
 598         .get_unmapped_area      = hugetlb_get_unmapped_area,
 599 };
 600
 601 static struct inode_operations hugetlbfs_dir_inode_operations = {
 602         .create         = hugetlbfs_create,
 603         .lookup         = simple_lookup,
 604         .link           = simple_link,
 605         .unlink         = simple_unlink,
 606         .symlink        = hugetlbfs_symlink,
 607         .mkdir          = hugetlbfs_mkdir,
 608         .rmdir          = simple_rmdir,
 609         .mknod          = hugetlbfs_mknod,
 610         .rename         = simple_rename,
 611         .setattr        = hugetlbfs_setattr,
 612 };
 613
 614 static struct inode_operations hugetlbfs_inode_operations = {
 615         .setattr        = hugetlbfs_setattr,
 616 };
 617
 618 static struct super_operations hugetlbfs_ops = {
 619         .alloc_inode    = hugetlbfs_alloc_inode,
 620         .destroy_inode  = hugetlbfs_destroy_inode,
 621         .statfs         = hugetlbfs_statfs,
 622         .delete_inode   = hugetlbfs_delete_inode,
 623         .drop_inode     = hugetlbfs_drop_inode,
 624         .put_super      = hugetlbfs_put_super,
 625 };
 626
 627 static int
 628 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
 629 {
 630         char *opt, *value, *rest;
 631
 632         if (!options)
 633                 return 0;
 634         while ((opt = strsep(&options, ",")) != NULL) {
 635                 if (!*opt)
 636                         continue;
 637
 638                 value = strchr(opt, '=');
 639                 if (!value || !*value)
 640                         return -EINVAL;
 641                 else
 642                         *value++ = '\0';
 643
 644                 if (!strcmp(opt, "uid"))
 645                         pconfig->uid = simple_strtoul(value, &value, 0);
 646                 else if (!strcmp(opt, "gid"))
 647                         pconfig->gid = simple_strtoul(value, &value, 0);
 648                 else if (!strcmp(opt, "mode"))
 649                         pconfig->mode = simple_strtoul(value,&value,0) & 0777U;
 650                 else if (!strcmp(opt, "size")) {
 651                         unsigned long long size = memparse(value, &rest);
 652                         if (*rest == '%') {
 653                                 size <<= HPAGE_SHIFT;
 654                                 size *= max_huge_pages;
 655                                 do_div(size, 100);
 656                                 rest++;
 657                         }
 658                         size &= HPAGE_MASK;
 659                         pconfig->nr_blocks = (size >> HPAGE_SHIFT);
 660                         value = rest;
 661                 } else if (!strcmp(opt,"nr_inodes")) {
 662                         pconfig->nr_inodes = memparse(value, &rest);
 663                         value = rest;
 664                 } else
 665                         return -EINVAL;
 666
 667                 if (*value)
 668                         return -EINVAL;
 669         }
 670         return 0;
 671 }
 672
 673 static int
 674 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
 675 {
 676         struct inode * inode;
 677         struct dentry * root;
 678         int ret;
 679         struct hugetlbfs_config config;
 680         struct hugetlbfs_sb_info *sbinfo;
 681
 682         config.nr_blocks = -1; /* No limit on size by default */
 683         config.nr_inodes = -1; /* No limit on number of inodes by default */
 684         config.uid = current->fsuid;
 685         config.gid = current->fsgid;
 686         config.mode = 0755;
 687         ret = hugetlbfs_parse_options(data, &config);
 688
 689         if (ret)
 690                 return ret;
 691
 692         sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
 693         if (!sbinfo)
 694                 return -ENOMEM;
 695         sb->s_fs_info = sbinfo;
 696         spin_lock_init(&sbinfo->stat_lock);
 697         sbinfo->max_blocks = config.nr_blocks;
 698         sbinfo->free_blocks = config.nr_blocks;
 699         sbinfo->max_inodes = config.nr_inodes;
 700         sbinfo->free_inodes = config.nr_inodes;
 701         sb->s_maxbytes = MAX_LFS_FILESIZE;
 702         sb->s_blocksize = HPAGE_SIZE;
 703         sb->s_blocksize_bits = HPAGE_SHIFT;
 704         sb->s_magic = HUGETLBFS_MAGIC;
 705         sb->s_op = &hugetlbfs_ops;
 706         sb->s_time_gran = 1;
 707         inode = hugetlbfs_get_inode(sb, config.uid, config.gid,
 708                                         S_IFDIR | config.mode, 0);
 709         if (!inode)
 710                 goto out_free;
 711
 712         root = d_alloc_root(inode);
 713         if (!root) {
 714                 iput(inode);
 715                 goto out_free;
 716         }
 717         sb->s_root = root;
 718         return 0;
 719 out_free:
 720         kfree(sbinfo);
 721         return -ENOMEM;
 722 }
 723
 724 int hugetlb_get_quota(struct address_space *mapping)
 725 {
 726         int ret = 0;
 727         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
 728
 729         if (sbinfo->free_blocks > -1) {
 730                 spin_lock(&sbinfo->stat_lock);
 731                 if (sbinfo->free_blocks > 0)
 732                         sbinfo->free_blocks--;
 733                 else
 734                         ret = -ENOMEM;
 735                 spin_unlock(&sbinfo->stat_lock);
 736         }
 737
 738         return ret;
 739 }
 740
 741 void hugetlb_put_quota(struct address_space *mapping)
 742 {
 743         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
 744
 745         if (sbinfo->free_blocks > -1) {
 746                 spin_lock(&sbinfo->stat_lock);
 747                 sbinfo->free_blocks++;
 748                 spin_unlock(&sbinfo->stat_lock);
 749         }
 750 }
 751
 752 static struct super_block *hugetlbfs_get_sb(struct file_system_type *fs_type,
 753         int flags, const char *dev_name, void *data)
 754 {
 755         return get_sb_nodev(fs_type, flags, data, hugetlbfs_fill_super);
 756 }
 757
 758 static struct file_system_type hugetlbfs_fs_type = {
 759         .name           = "hugetlbfs",
 760         .get_sb         = hugetlbfs_get_sb,
 761         .kill_sb        = kill_litter_super,
 762 };
 763
 764 static struct vfsmount *hugetlbfs_vfsmount;
 765
 766 /*
 767  * Return the next identifier for a shm file
 768  */
 769 static unsigned long hugetlbfs_counter(void)
 770 {
 771         static DEFINE_SPINLOCK(lock);
 772         static unsigned long counter;
 773         unsigned long ret;
 774
 775         spin_lock(&lock);
 776         ret = ++counter;
 777         spin_unlock(&lock);
 778         return ret;
 779 }
 780
 781 static int can_do_hugetlb_shm(void)
 782 {
 783         return likely(capable(CAP_IPC_LOCK) ||
 784                         in_group_p(sysctl_hugetlb_shm_group) ||
 785                         can_do_mlock());
 786 }
 787
 788 struct file *hugetlb_zero_setup(size_t size)
 789 {
 790         int error = -ENOMEM;
 791         struct file *file;
 792         struct inode *inode;
 793         struct dentry *dentry, *root;
 794         struct qstr quick_string;
 795         char buf[16];
 796
 797         if (!can_do_hugetlb_shm())
 798                 return ERR_PTR(-EPERM);
 799
 800         if (!is_hugepage_mem_enough(size))
 801                 return ERR_PTR(-ENOMEM);
 802
 803         if (!user_shm_lock(size, current->user))
 804                 return ERR_PTR(-ENOMEM);
 805
 806         root = hugetlbfs_vfsmount->mnt_root;
 807         snprintf(buf, 16, "%lu", hugetlbfs_counter());
 808         quick_string.name = buf;
 809         quick_string.len = strlen(quick_string.name);
 810         quick_string.hash = 0;
 811         dentry = d_alloc(root, &quick_string);
 812         if (!dentry)
 813                 goto out_shm_unlock;
 814
 815         error = -ENFILE;
 816         file = get_empty_filp();
 817         if (!file)
 818                 goto out_dentry;
 819
 820         error = -ENOSPC;
 821         inode = hugetlbfs_get_inode(root->d_sb, current->fsuid,
 822                                 current->fsgid, S_IFREG | S_IRWXUGO, 0);
 823         if (!inode)
 824                 goto out_file;
 825
 826         d_instantiate(dentry, inode);
 827         inode->i_size = size;
 828         inode->i_nlink = 0;
 829         file->f_vfsmnt = mntget(hugetlbfs_vfsmount);
 830         file->f_dentry = dentry;
 831         file->f_mapping = inode->i_mapping;
 832         file->f_op = &hugetlbfs_file_operations;
 833         file->f_mode = FMODE_WRITE | FMODE_READ;
 834         return file;
 835
 836 out_file:
 837         put_filp(file);
 838 out_dentry:
 839         dput(dentry);
 840 out_shm_unlock:
 841         user_shm_unlock(size, current->user);
 842         return ERR_PTR(error);
 843 }
 844
 845 static int __init init_hugetlbfs_fs(void)
 846 {
 847         int error;
 848         struct vfsmount *vfsmount;
 849
 850         hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
 851                                         sizeof(struct hugetlbfs_inode_info),
 852                                         0, 0, init_once, NULL);
 853         if (hugetlbfs_inode_cachep == NULL)
 854                 return -ENOMEM;
 855
 856         error = register_filesystem(&hugetlbfs_fs_type);
 857         if (error)
 858                 goto out;
 859
 860         vfsmount = kern_mount(&hugetlbfs_fs_type);
 861
 862         if (!IS_ERR(vfsmount)) {
 863                 hugetlbfs_vfsmount = vfsmount;
 864                 return 0;
 865         }
 866
 867         error = PTR_ERR(vfsmount);
 868
 869  out:
 870         if (error)
 871                 kmem_cache_destroy(hugetlbfs_inode_cachep);
 872         return error;
 873 }
 874
 875 static void __exit exit_hugetlbfs_fs(void)
 876 {
 877         kmem_cache_destroy(hugetlbfs_inode_cachep);
 878         unregister_filesystem(&hugetlbfs_fs_type);
 879 }
 880
 881 module_init(init_hugetlbfs_fs)
 882 module_exit(exit_hugetlbfs_fs)
 883
 884 MODULE_LICENSE("GPL");