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/slab.h>
  30 #include <linux/dnotify.h>
  31 #include <linux/statfs.h>
  32 #include <linux/security.h>
  33 #include <linux/magic.h>
  34 #include <linux/migrate.h>
  35
  36 #include <asm/uaccess.h>
  37
  38 static const struct super_operations hugetlbfs_ops;
  39 static const struct address_space_operations hugetlbfs_aops;
  40 const struct file_operations hugetlbfs_file_operations;
  41 static const struct inode_operations hugetlbfs_dir_inode_operations;
  42 static const struct inode_operations hugetlbfs_inode_operations;
  43
  44 struct hugetlbfs_config {
  45         uid_t   uid;
  46         gid_t   gid;
  47         umode_t mode;
  48         long    nr_blocks;
  49         long    nr_inodes;
  50         struct hstate *hstate;
  51 };
  52
  53 struct hugetlbfs_inode_info {
  54         struct shared_policy policy;
  55         struct inode vfs_inode;
  56 };
  57
  58 static inline struct hugetlbfs_inode_info *HUGETLBFS_I(struct inode *inode)
  59 {
  60         return container_of(inode, struct hugetlbfs_inode_info, vfs_inode);
  61 }
  62
  63 static struct backing_dev_info hugetlbfs_backing_dev_info = {
  64         .name           = "hugetlbfs",
  65         .ra_pages       = 0,    /* No readahead */
  66         .capabilities   = BDI_CAP_NO_ACCT_AND_WRITEBACK,
  67 };
  68
  69 int sysctl_hugetlb_shm_group;
  70
  71 enum {
  72         Opt_size, Opt_nr_inodes,
  73         Opt_mode, Opt_uid, Opt_gid,
  74         Opt_pagesize,
  75         Opt_err,
  76 };
  77
  78 static const match_table_t tokens = {
  79         {Opt_size,      "size=%s"},
  80         {Opt_nr_inodes, "nr_inodes=%s"},
  81         {Opt_mode,      "mode=%o"},
  82         {Opt_uid,       "uid=%u"},
  83         {Opt_gid,       "gid=%u"},
  84         {Opt_pagesize,  "pagesize=%s"},
  85         {Opt_err,       NULL},
  86 };
  87
  88 static void huge_pagevec_release(struct pagevec *pvec)
  89 {
  90         int i;
  91
  92         for (i = 0; i < pagevec_count(pvec); ++i)
  93                 put_page(pvec->pages[i]);
  94
  95         pagevec_reinit(pvec);
  96 }
  97
  98 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
  99 {
 100         struct inode *inode = file->f_path.dentry->d_inode;
 101         loff_t len, vma_len;
 102         int ret;
 103         struct hstate *h = hstate_file(file);
 104
 105         /*
 106          * vma address alignment (but not the pgoff alignment) has
 107          * already been checked by prepare_hugepage_range.  If you add
 108          * any error returns here, do so after setting VM_HUGETLB, so
 109          * is_vm_hugetlb_page tests below unmap_region go the right
 110          * way when do_mmap_pgoff unwinds (may be important on powerpc
 111          * and ia64).
 112          */
 113         vma->vm_flags |= VM_HUGETLB | VM_RESERVED;
 114         vma->vm_ops = &hugetlb_vm_ops;
 115
 116         if (vma->vm_pgoff & (~huge_page_mask(h) >> PAGE_SHIFT))
 117                 return -EINVAL;
 118
 119         vma_len = (loff_t)(vma->vm_end - vma->vm_start);
 120
 121         mutex_lock(&inode->i_mutex);
 122         file_accessed(file);
 123
 124         ret = -ENOMEM;
 125         len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
 126
 127         if (hugetlb_reserve_pages(inode,
 128                                 vma->vm_pgoff >> huge_page_order(h),
 129                                 len >> huge_page_shift(h), vma,
 130                                 vma->vm_flags))
 131                 goto out;
 132
 133         ret = 0;
 134         hugetlb_prefault_arch_hook(vma->vm_mm);
 135         if (vma->vm_flags & VM_WRITE && inode->i_size < len)
 136                 inode->i_size = len;
 137 out:
 138         mutex_unlock(&inode->i_mutex);
 139
 140         return ret;
 141 }
 142
 143 /*
 144  * Called under down_write(mmap_sem).
 145  */
 146
 147 #ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
 148 static unsigned long
 149 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 150                 unsigned long len, unsigned long pgoff, unsigned long flags)
 151 {
 152         struct mm_struct *mm = current->mm;
 153         struct vm_area_struct *vma;
 154         unsigned long start_addr;
 155         struct hstate *h = hstate_file(file);
 156
 157         if (len & ~huge_page_mask(h))
 158                 return -EINVAL;
 159         if (len > TASK_SIZE)
 160                 return -ENOMEM;
 161
 162         if (flags & MAP_FIXED) {
 163                 if (prepare_hugepage_range(file, addr, len))
 164                         return -EINVAL;
 165                 return addr;
 166         }
 167
 168         if (addr) {
 169                 addr = ALIGN(addr, huge_page_size(h));
 170                 vma = find_vma(mm, addr);
 171                 if (TASK_SIZE - len >= addr &&
 172                     (!vma || addr + len <= vma->vm_start))
 173                         return addr;
 174         }
 175
 176         if (len > mm->cached_hole_size)
 177                 start_addr = mm->free_area_cache;
 178         else {
 179                 start_addr = TASK_UNMAPPED_BASE;
 180                 mm->cached_hole_size = 0;
 181         }
 182
 183 full_search:
 184         addr = ALIGN(start_addr, huge_page_size(h));
 185
 186         for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
 187                 /* At this point:  (!vma || addr < vma->vm_end). */
 188                 if (TASK_SIZE - len < addr) {
 189                         /*
 190                          * Start a new search - just in case we missed
 191                          * some holes.
 192                          */
 193                         if (start_addr != TASK_UNMAPPED_BASE) {
 194                                 start_addr = TASK_UNMAPPED_BASE;
 195                                 mm->cached_hole_size = 0;
 196                                 goto full_search;
 197                         }
 198                         return -ENOMEM;
 199                 }
 200
 201                 if (!vma || addr + len <= vma->vm_start) {
 202                         mm->free_area_cache = addr + len;
 203                         return addr;
 204                 }
 205                 if (addr + mm->cached_hole_size < vma->vm_start)
 206                         mm->cached_hole_size = vma->vm_start - addr;
 207                 addr = ALIGN(vma->vm_end, huge_page_size(h));
 208         }
 209 }
 210 #endif
 211
 212 static int
 213 hugetlbfs_read_actor(struct page *page, unsigned long offset,
 214                         char __user *buf, unsigned long count,
 215                         unsigned long size)
 216 {
 217         char *kaddr;
 218         unsigned long left, copied = 0;
 219         int i, chunksize;
 220
 221         if (size > count)
 222                 size = count;
 223
 224         /* Find which 4k chunk and offset with in that chunk */
 225         i = offset >> PAGE_CACHE_SHIFT;
 226         offset = offset & ~PAGE_CACHE_MASK;
 227
 228         while (size) {
 229                 chunksize = PAGE_CACHE_SIZE;
 230                 if (offset)
 231                         chunksize -= offset;
 232                 if (chunksize > size)
 233                         chunksize = size;
 234                 kaddr = kmap(&page[i]);
 235                 left = __copy_to_user(buf, kaddr + offset, chunksize);
 236                 kunmap(&page[i]);
 237                 if (left) {
 238                         copied += (chunksize - left);
 239                         break;
 240                 }
 241                 offset = 0;
 242                 size -= chunksize;
 243                 buf += chunksize;
 244                 copied += chunksize;
 245                 i++;
 246         }
 247         return copied ? copied : -EFAULT;
 248 }
 249
 250 /*
 251  * Support for read() - Find the page attached to f_mapping and copy out the
 252  * data. Its *very* similar to do_generic_mapping_read(), we can't use that
 253  * since it has PAGE_CACHE_SIZE assumptions.
 254  */
 255 static ssize_t hugetlbfs_read(struct file *filp, char __user *buf,
 256                               size_t len, loff_t *ppos)
 257 {
 258         struct hstate *h = hstate_file(filp);
 259         struct address_space *mapping = filp->f_mapping;
 260         struct inode *inode = mapping->host;
 261         unsigned long index = *ppos >> huge_page_shift(h);
 262         unsigned long offset = *ppos & ~huge_page_mask(h);
 263         unsigned long end_index;
 264         loff_t isize;
 265         ssize_t retval = 0;
 266
 267         /* validate length */
 268         if (len == 0)
 269                 goto out;
 270
 271         for (;;) {
 272                 struct page *page;
 273                 unsigned long nr, ret;
 274                 int ra;
 275
 276                 /* nr is the maximum number of bytes to copy from this page */
 277                 nr = huge_page_size(h);
 278                 isize = i_size_read(inode);
 279                 if (!isize)
 280                         goto out;
 281                 end_index = (isize - 1) >> huge_page_shift(h);
 282                 if (index >= end_index) {
 283                         if (index > end_index)
 284                                 goto out;
 285                         nr = ((isize - 1) & ~huge_page_mask(h)) + 1;
 286                         if (nr <= offset)
 287                                 goto out;
 288                 }
 289                 nr = nr - offset;
 290
 291                 /* Find the page */
 292                 page = find_lock_page(mapping, index);
 293                 if (unlikely(page == NULL)) {
 294                         /*
 295                          * We have a HOLE, zero out the user-buffer for the
 296                          * length of the hole or request.
 297                          */
 298                         ret = len < nr ? len : nr;
 299                         if (clear_user(buf, ret))
 300                                 ra = -EFAULT;
 301                         else
 302                                 ra = 0;
 303                 } else {
 304                         unlock_page(page);
 305
 306                         /*
 307                          * We have the page, copy it to user space buffer.
 308                          */
 309                         ra = hugetlbfs_read_actor(page, offset, buf, len, nr);
 310                         ret = ra;
 311                         page_cache_release(page);
 312                 }
 313                 if (ra < 0) {
 314                         if (retval == 0)
 315                                 retval = ra;
 316                         goto out;
 317                 }
 318
 319                 offset += ret;
 320                 retval += ret;
 321                 len -= ret;
 322                 index += offset >> huge_page_shift(h);
 323                 offset &= ~huge_page_mask(h);
 324
 325                 /* short read or no more work */
 326                 if ((ret != nr) || (len == 0))
 327                         break;
 328         }
 329 out:
 330         *ppos = ((loff_t)index << huge_page_shift(h)) + offset;
 331         return retval;
 332 }
 333
 334 static int hugetlbfs_write_begin(struct file *file,
 335                         struct address_space *mapping,
 336                         loff_t pos, unsigned len, unsigned flags,
 337                         struct page **pagep, void **fsdata)
 338 {
 339         return -EINVAL;
 340 }
 341
 342 static int hugetlbfs_write_end(struct file *file, struct address_space *mapping,
 343                         loff_t pos, unsigned len, unsigned copied,
 344                         struct page *page, void *fsdata)
 345 {
 346         BUG();
 347         return -EINVAL;
 348 }
 349
 350 static void truncate_huge_page(struct page *page)
 351 {
 352         cancel_dirty_page(page, /* No IO accounting for huge pages? */0);
 353         ClearPageUptodate(page);
 354         delete_from_page_cache(page);
 355 }
 356
 357 static void truncate_hugepages(struct inode *inode, loff_t lstart)
 358 {
 359         struct hstate *h = hstate_inode(inode);
 360         struct address_space *mapping = &inode->i_data;
 361         const pgoff_t start = lstart >> huge_page_shift(h);
 362         struct pagevec pvec;
 363         pgoff_t next;
 364         int i, freed = 0;
 365
 366         pagevec_init(&pvec, 0);
 367         next = start;
 368         while (1) {
 369                 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
 370                         if (next == start)
 371                                 break;
 372                         next = start;
 373                         continue;
 374                 }
 375
 376                 for (i = 0; i < pagevec_count(&pvec); ++i) {
 377                         struct page *page = pvec.pages[i];
 378
 379                         lock_page(page);
 380                         if (page->index > next)
 381                                 next = page->index;
 382                         ++next;
 383                         truncate_huge_page(page);
 384                         unlock_page(page);
 385                         freed++;
 386                 }
 387                 huge_pagevec_release(&pvec);
 388         }
 389         BUG_ON(!lstart && mapping->nrpages);
 390         hugetlb_unreserve_pages(inode, start, freed);
 391 }
 392
 393 static void hugetlbfs_evict_inode(struct inode *inode)
 394 {
 395         truncate_hugepages(inode, 0);
 396         clear_inode(inode);
 397 }
 398
 399 static inline void
 400 hugetlb_vmtruncate_list(struct prio_tree_root *root, pgoff_t pgoff)
 401 {
 402         struct vm_area_struct *vma;
 403         struct prio_tree_iter iter;
 404
 405         vma_prio_tree_foreach(vma, &iter, root, pgoff, ULONG_MAX) {
 406                 unsigned long v_offset;
 407
 408                 /*
 409                  * Can the expression below overflow on 32-bit arches?
 410                  * No, because the prio_tree returns us only those vmas
 411                  * which overlap the truncated area starting at pgoff,
 412                  * and no vma on a 32-bit arch can span beyond the 4GB.
 413                  */
 414                 if (vma->vm_pgoff < pgoff)
 415                         v_offset = (pgoff - vma->vm_pgoff) << PAGE_SHIFT;
 416                 else
 417                         v_offset = 0;
 418
 419                 __unmap_hugepage_range(vma,
 420                                 vma->vm_start + v_offset, vma->vm_end, NULL);
 421         }
 422 }
 423
 424 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
 425 {
 426         pgoff_t pgoff;
 427         struct address_space *mapping = inode->i_mapping;
 428         struct hstate *h = hstate_inode(inode);
 429
 430         BUG_ON(offset & ~huge_page_mask(h));
 431         pgoff = offset >> PAGE_SHIFT;
 432
 433         i_size_write(inode, offset);
 434         mutex_lock(&mapping->i_mmap_mutex);
 435         if (!prio_tree_empty(&mapping->i_mmap))
 436                 hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff);
 437         mutex_unlock(&mapping->i_mmap_mutex);
 438         truncate_hugepages(inode, offset);
 439         return 0;
 440 }
 441
 442 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
 443 {
 444         struct inode *inode = dentry->d_inode;
 445         struct hstate *h = hstate_inode(inode);
 446         int error;
 447         unsigned int ia_valid = attr->ia_valid;
 448
 449         BUG_ON(!inode);
 450
 451         error = inode_change_ok(inode, attr);
 452         if (error)
 453                 return error;
 454
 455         if (ia_valid & ATTR_SIZE) {
 456                 error = -EINVAL;
 457                 if (attr->ia_size & ~huge_page_mask(h))
 458                         return -EINVAL;
 459                 error = hugetlb_vmtruncate(inode, attr->ia_size);
 460                 if (error)
 461                         return error;
 462         }
 463
 464         setattr_copy(inode, attr);
 465         mark_inode_dirty(inode);
 466         return 0;
 467 }
 468
 469 static struct inode *hugetlbfs_get_root(struct super_block *sb,
 470                                         struct hugetlbfs_config *config)
 471 {
 472         struct inode *inode;
 473
 474         inode = new_inode(sb);
 475         if (inode) {
 476                 struct hugetlbfs_inode_info *info;
 477                 inode->i_ino = get_next_ino();
 478                 inode->i_mode = S_IFDIR | config->mode;
 479                 inode->i_uid = config->uid;
 480                 inode->i_gid = config->gid;
 481                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 482                 info = HUGETLBFS_I(inode);
 483                 mpol_shared_policy_init(&info->policy, NULL);
 484                 inode->i_op = &hugetlbfs_dir_inode_operations;
 485                 inode->i_fop = &simple_dir_operations;
 486                 /* directory inodes start off with i_nlink == 2 (for "." entry) */
 487                 inc_nlink(inode);
 488                 lockdep_annotate_inode_mutex_key(inode);
 489         }
 490         return inode;
 491 }
 492
 493 static struct inode *hugetlbfs_get_inode(struct super_block *sb,
 494                                         struct inode *dir,
 495                                         umode_t mode, dev_t dev)
 496 {
 497         struct inode *inode;
 498
 499         inode = new_inode(sb);
 500         if (inode) {
 501                 struct hugetlbfs_inode_info *info;
 502                 inode->i_ino = get_next_ino();
 503                 inode_init_owner(inode, dir, mode);
 504                 inode->i_mapping->a_ops = &hugetlbfs_aops;
 505                 inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info;
 506                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 507                 INIT_LIST_HEAD(&inode->i_mapping->private_list);
 508                 info = HUGETLBFS_I(inode);
 509                 /*
 510                  * The policy is initialized here even if we are creating a
 511                  * private inode because initialization simply creates an
 512                  * an empty rb tree and calls spin_lock_init(), later when we
 513                  * call mpol_free_shared_policy() it will just return because
 514                  * the rb tree will still be empty.
 515                  */
 516                 mpol_shared_policy_init(&info->policy, NULL);
 517                 switch (mode & S_IFMT) {
 518                 default:
 519                         init_special_inode(inode, mode, dev);
 520                         break;
 521                 case S_IFREG:
 522                         inode->i_op = &hugetlbfs_inode_operations;
 523                         inode->i_fop = &hugetlbfs_file_operations;
 524                         break;
 525                 case S_IFDIR:
 526                         inode->i_op = &hugetlbfs_dir_inode_operations;
 527                         inode->i_fop = &simple_dir_operations;
 528
 529                         /* directory inodes start off with i_nlink == 2 (for "." entry) */
 530                         inc_nlink(inode);
 531                         break;
 532                 case S_IFLNK:
 533                         inode->i_op = &page_symlink_inode_operations;
 534                         break;
 535                 }
 536                 lockdep_annotate_inode_mutex_key(inode);
 537         }
 538         return inode;
 539 }
 540
 541 /*
 542  * File creation. Allocate an inode, and we're done..
 543  */
 544 static int hugetlbfs_mknod(struct inode *dir,
 545                         struct dentry *dentry, umode_t mode, dev_t dev)
 546 {
 547         struct inode *inode;
 548         int error = -ENOSPC;
 549
 550         inode = hugetlbfs_get_inode(dir->i_sb, dir, mode, dev);
 551         if (inode) {
 552                 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 553                 d_instantiate(dentry, inode);
 554                 dget(dentry);   /* Extra count - pin the dentry in core */
 555                 error = 0;
 556         }
 557         return error;
 558 }
 559
 560 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 561 {
 562         int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
 563         if (!retval)
 564                 inc_nlink(dir);
 565         return retval;
 566 }
 567
 568 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, struct nameidata *nd)
 569 {
 570         return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
 571 }
 572
 573 static int hugetlbfs_symlink(struct inode *dir,
 574                         struct dentry *dentry, const char *symname)
 575 {
 576         struct inode *inode;
 577         int error = -ENOSPC;
 578
 579         inode = hugetlbfs_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0);
 580         if (inode) {
 581                 int l = strlen(symname)+1;
 582                 error = page_symlink(inode, symname, l);
 583                 if (!error) {
 584                         d_instantiate(dentry, inode);
 585                         dget(dentry);
 586                 } else
 587                         iput(inode);
 588         }
 589         dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 590
 591         return error;
 592 }
 593
 594 /*
 595  * mark the head page dirty
 596  */
 597 static int hugetlbfs_set_page_dirty(struct page *page)
 598 {
 599         struct page *head = compound_head(page);
 600
 601         SetPageDirty(head);
 602         return 0;
 603 }
 604
 605 static int hugetlbfs_migrate_page(struct address_space *mapping,
 606                                 struct page *newpage, struct page *page,
 607                                 enum migrate_mode mode)
 608 {
 609         int rc;
 610
 611         rc = migrate_huge_page_move_mapping(mapping, newpage, page);
 612         if (rc)
 613                 return rc;
 614         migrate_page_copy(newpage, page);
 615
 616         return 0;
 617 }
 618
 619 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 620 {
 621         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
 622         struct hstate *h = hstate_inode(dentry->d_inode);
 623
 624         buf->f_type = HUGETLBFS_MAGIC;
 625         buf->f_bsize = huge_page_size(h);
 626         if (sbinfo) {
 627                 spin_lock(&sbinfo->stat_lock);
 628                 /* If no limits set, just report 0 for max/free/used
 629                  * blocks, like simple_statfs() */
 630                 if (sbinfo->spool) {
 631                         long free_pages;
 632
 633                         spin_lock(&sbinfo->spool->lock);
 634                         buf->f_blocks = sbinfo->spool->max_hpages;
 635                         free_pages = sbinfo->spool->max_hpages
 636                                 - sbinfo->spool->used_hpages;
 637                         buf->f_bavail = buf->f_bfree = free_pages;
 638                         spin_unlock(&sbinfo->spool->lock);
 639                         buf->f_files = sbinfo->max_inodes;
 640                         buf->f_ffree = sbinfo->free_inodes;
 641                 }
 642                 spin_unlock(&sbinfo->stat_lock);
 643         }
 644         buf->f_namelen = NAME_MAX;
 645         return 0;
 646 }
 647
 648 static void hugetlbfs_put_super(struct super_block *sb)
 649 {
 650         struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
 651
 652         if (sbi) {
 653                 sb->s_fs_info = NULL;
 654
 655                 if (sbi->spool)
 656                         hugepage_put_subpool(sbi->spool);
 657
 658                 kfree(sbi);
 659         }
 660 }
 661
 662 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
 663 {
 664         if (sbinfo->free_inodes >= 0) {
 665                 spin_lock(&sbinfo->stat_lock);
 666                 if (unlikely(!sbinfo->free_inodes)) {
 667                         spin_unlock(&sbinfo->stat_lock);
 668                         return 0;
 669                 }
 670                 sbinfo->free_inodes--;
 671                 spin_unlock(&sbinfo->stat_lock);
 672         }
 673
 674         return 1;
 675 }
 676
 677 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
 678 {
 679         if (sbinfo->free_inodes >= 0) {
 680                 spin_lock(&sbinfo->stat_lock);
 681                 sbinfo->free_inodes++;
 682                 spin_unlock(&sbinfo->stat_lock);
 683         }
 684 }
 685
 686
 687 static struct kmem_cache *hugetlbfs_inode_cachep;
 688
 689 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
 690 {
 691         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
 692         struct hugetlbfs_inode_info *p;
 693
 694         if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
 695                 return NULL;
 696         p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL);
 697         if (unlikely(!p)) {
 698                 hugetlbfs_inc_free_inodes(sbinfo);
 699                 return NULL;
 700         }
 701         return &p->vfs_inode;
 702 }
 703
 704 static void hugetlbfs_i_callback(struct rcu_head *head)
 705 {
 706         struct inode *inode = container_of(head, struct inode, i_rcu);
 707         kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
 708 }
 709
 710 static void hugetlbfs_destroy_inode(struct inode *inode)
 711 {
 712         hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
 713         mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
 714         call_rcu(&inode->i_rcu, hugetlbfs_i_callback);
 715 }
 716
 717 static const struct address_space_operations hugetlbfs_aops = {
 718         .write_begin    = hugetlbfs_write_begin,
 719         .write_end      = hugetlbfs_write_end,
 720         .set_page_dirty = hugetlbfs_set_page_dirty,
 721         .migratepage    = hugetlbfs_migrate_page,
 722 };
 723
 724
 725 static void init_once(void *foo)
 726 {
 727         struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
 728
 729         inode_init_once(&ei->vfs_inode);
 730 }
 731
 732 const struct file_operations hugetlbfs_file_operations = {
 733         .read                   = hugetlbfs_read,
 734         .mmap                   = hugetlbfs_file_mmap,
 735         .fsync                  = noop_fsync,
 736         .get_unmapped_area      = hugetlb_get_unmapped_area,
 737         .llseek         = default_llseek,
 738 };
 739
 740 static const struct inode_operations hugetlbfs_dir_inode_operations = {
 741         .create         = hugetlbfs_create,
 742         .lookup         = simple_lookup,
 743         .link           = simple_link,
 744         .unlink         = simple_unlink,
 745         .symlink        = hugetlbfs_symlink,
 746         .mkdir          = hugetlbfs_mkdir,
 747         .rmdir          = simple_rmdir,
 748         .mknod          = hugetlbfs_mknod,
 749         .rename         = simple_rename,
 750         .setattr        = hugetlbfs_setattr,
 751 };
 752
 753 static const struct inode_operations hugetlbfs_inode_operations = {
 754         .setattr        = hugetlbfs_setattr,
 755 };
 756
 757 static const struct super_operations hugetlbfs_ops = {
 758         .alloc_inode    = hugetlbfs_alloc_inode,
 759         .destroy_inode  = hugetlbfs_destroy_inode,
 760         .evict_inode    = hugetlbfs_evict_inode,
 761         .statfs         = hugetlbfs_statfs,
 762         .put_super      = hugetlbfs_put_super,
 763         .show_options   = generic_show_options,
 764 };
 765
 766 static int
 767 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
 768 {
 769         char *p, *rest;
 770         substring_t args[MAX_OPT_ARGS];
 771         int option;
 772         unsigned long long size = 0;
 773         enum { NO_SIZE, SIZE_STD, SIZE_PERCENT } setsize = NO_SIZE;
 774
 775         if (!options)
 776                 return 0;
 777
 778         while ((p = strsep(&options, ",")) != NULL) {
 779                 int token;
 780                 if (!*p)
 781                         continue;
 782
 783                 token = match_token(p, tokens, args);
 784                 switch (token) {
 785                 case Opt_uid:
 786                         if (match_int(&args[0], &option))
 787                                 goto bad_val;
 788                         pconfig->uid = option;
 789                         break;
 790
 791                 case Opt_gid:
 792                         if (match_int(&args[0], &option))
 793                                 goto bad_val;
 794                         pconfig->gid = option;
 795                         break;
 796
 797                 case Opt_mode:
 798                         if (match_octal(&args[0], &option))
 799                                 goto bad_val;
 800                         pconfig->mode = option & 01777U;
 801                         break;
 802
 803                 case Opt_size: {
 804                         /* memparse() will accept a K/M/G without a digit */
 805                         if (!isdigit(*args[0].from))
 806                                 goto bad_val;
 807                         size = memparse(args[0].from, &rest);
 808                         setsize = SIZE_STD;
 809                         if (*rest == '%')
 810                                 setsize = SIZE_PERCENT;
 811                         break;
 812                 }
 813
 814                 case Opt_nr_inodes:
 815                         /* memparse() will accept a K/M/G without a digit */
 816                         if (!isdigit(*args[0].from))
 817                                 goto bad_val;
 818                         pconfig->nr_inodes = memparse(args[0].from, &rest);
 819                         break;
 820
 821                 case Opt_pagesize: {
 822                         unsigned long ps;
 823                         ps = memparse(args[0].from, &rest);
 824                         pconfig->hstate = size_to_hstate(ps);
 825                         if (!pconfig->hstate) {
 826                                 printk(KERN_ERR
 827                                 "hugetlbfs: Unsupported page size %lu MB\n",
 828                                         ps >> 20);
 829                                 return -EINVAL;
 830                         }
 831                         break;
 832                 }
 833
 834                 default:
 835                         printk(KERN_ERR "hugetlbfs: Bad mount option: \"%s\"\n",
 836                                  p);
 837                         return -EINVAL;
 838                         break;
 839                 }
 840         }
 841
 842         /* Do size after hstate is set up */
 843         if (setsize > NO_SIZE) {
 844                 struct hstate *h = pconfig->hstate;
 845                 if (setsize == SIZE_PERCENT) {
 846                         size <<= huge_page_shift(h);
 847                         size *= h->max_huge_pages;
 848                         do_div(size, 100);
 849                 }
 850                 pconfig->nr_blocks = (size >> huge_page_shift(h));
 851         }
 852
 853         return 0;
 854
 855 bad_val:
 856         printk(KERN_ERR "hugetlbfs: Bad value '%s' for mount option '%s'\n",
 857                args[0].from, p);
 858         return -EINVAL;
 859 }
 860
 861 static int
 862 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
 863 {
 864         int ret;
 865         struct hugetlbfs_config config;
 866         struct hugetlbfs_sb_info *sbinfo;
 867
 868         save_mount_options(sb, data);
 869
 870         config.nr_blocks = -1; /* No limit on size by default */
 871         config.nr_inodes = -1; /* No limit on number of inodes by default */
 872         config.uid = current_fsuid();
 873         config.gid = current_fsgid();
 874         config.mode = 0755;
 875         config.hstate = &default_hstate;
 876         ret = hugetlbfs_parse_options(data, &config);
 877         if (ret)
 878                 return ret;
 879
 880         sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
 881         if (!sbinfo)
 882                 return -ENOMEM;
 883         sb->s_fs_info = sbinfo;
 884         sbinfo->hstate = config.hstate;
 885         spin_lock_init(&sbinfo->stat_lock);
 886         sbinfo->max_inodes = config.nr_inodes;
 887         sbinfo->free_inodes = config.nr_inodes;
 888         sbinfo->spool = NULL;
 889         if (config.nr_blocks != -1) {
 890                 sbinfo->spool = hugepage_new_subpool(config.nr_blocks);
 891                 if (!sbinfo->spool)
 892                         goto out_free;
 893         }
 894         sb->s_maxbytes = MAX_LFS_FILESIZE;
 895         sb->s_blocksize = huge_page_size(config.hstate);
 896         sb->s_blocksize_bits = huge_page_shift(config.hstate);
 897         sb->s_magic = HUGETLBFS_MAGIC;
 898         sb->s_op = &hugetlbfs_ops;
 899         sb->s_time_gran = 1;
 900         sb->s_root = d_make_root(hugetlbfs_get_root(sb, &config));
 901         if (!sb->s_root)
 902                 goto out_free;
 903         return 0;
 904 out_free:
 905         if (sbinfo->spool)
 906                 kfree(sbinfo->spool);
 907         kfree(sbinfo);
 908         return -ENOMEM;
 909 }
 910
 911 static struct dentry *hugetlbfs_mount(struct file_system_type *fs_type,
 912         int flags, const char *dev_name, void *data)
 913 {
 914         return mount_nodev(fs_type, flags, data, hugetlbfs_fill_super);
 915 }
 916
 917 static struct file_system_type hugetlbfs_fs_type = {
 918         .name           = "hugetlbfs",
 919         .mount          = hugetlbfs_mount,
 920         .kill_sb        = kill_litter_super,
 921 };
 922
 923 static struct vfsmount *hugetlbfs_vfsmount;
 924
 925 static int can_do_hugetlb_shm(void)
 926 {
 927         return capable(CAP_IPC_LOCK) || in_group_p(sysctl_hugetlb_shm_group);
 928 }
 929
 930 struct file *hugetlb_file_setup(const char *name, unsigned long addr,
 931                                 size_t size, vm_flags_t acctflag,
 932                                 struct user_struct **user, int creat_flags)
 933 {
 934         int error = -ENOMEM;
 935         struct file *file;
 936         struct inode *inode;
 937         struct path path;
 938         struct dentry *root;
 939         struct qstr quick_string;
 940         struct hstate *hstate;
 941         unsigned long num_pages;
 942
 943         *user = NULL;
 944         if (!hugetlbfs_vfsmount)
 945                 return ERR_PTR(-ENOENT);
 946
 947         if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) {
 948                 *user = current_user();
 949                 if (user_shm_lock(size, *user)) {
 950                         task_lock(current);
 951                         printk_once(KERN_WARNING
 952                                 "%s (%d): Using mlock ulimits for SHM_HUGETLB is deprecated\n",
 953                                 current->comm, current->pid);
 954                         task_unlock(current);
 955                 } else {
 956                         *user = NULL;
 957                         return ERR_PTR(-EPERM);
 958                 }
 959         }
 960
 961         root = hugetlbfs_vfsmount->mnt_root;
 962         quick_string.name = name;
 963         quick_string.len = strlen(quick_string.name);
 964         quick_string.hash = 0;
 965         path.dentry = d_alloc(root, &quick_string);
 966         if (!path.dentry)
 967                 goto out_shm_unlock;
 968
 969         path.mnt = mntget(hugetlbfs_vfsmount);
 970         error = -ENOSPC;
 971         inode = hugetlbfs_get_inode(root->d_sb, NULL, S_IFREG | S_IRWXUGO, 0);
 972         if (!inode)
 973                 goto out_dentry;
 974
 975         hstate = hstate_inode(inode);
 976         size += addr & ~huge_page_mask(hstate);
 977         num_pages = ALIGN(size, huge_page_size(hstate)) >>
 978                         huge_page_shift(hstate);
 979         error = -ENOMEM;
 980         if (hugetlb_reserve_pages(inode, 0, num_pages, NULL, acctflag))
 981                 goto out_inode;
 982
 983         d_instantiate(path.dentry, inode);
 984         inode->i_size = size;
 985         clear_nlink(inode);
 986
 987         error = -ENFILE;
 988         file = alloc_file(&path, FMODE_WRITE | FMODE_READ,
 989                         &hugetlbfs_file_operations);
 990         if (!file)
 991                 goto out_dentry; /* inode is already attached */
 992
 993         return file;
 994
 995 out_inode:
 996         iput(inode);
 997 out_dentry:
 998         path_put(&path);
 999 out_shm_unlock:
1000         if (*user) {
1001                 user_shm_unlock(size, *user);
1002                 *user = NULL;
1003         }
1004         return ERR_PTR(error);
1005 }
1006
1007 static int __init init_hugetlbfs_fs(void)
1008 {
1009         int error;
1010         struct vfsmount *vfsmount;
1011
1012         error = bdi_init(&hugetlbfs_backing_dev_info);
1013         if (error)
1014                 return error;
1015
1016         error = -ENOMEM;
1017         hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
1018                                         sizeof(struct hugetlbfs_inode_info),
1019                                         0, 0, init_once);
1020         if (hugetlbfs_inode_cachep == NULL)
1021                 goto out2;
1022
1023         error = register_filesystem(&hugetlbfs_fs_type);
1024         if (error)
1025                 goto out;
1026
1027         vfsmount = kern_mount(&hugetlbfs_fs_type);
1028
1029         if (!IS_ERR(vfsmount)) {
1030                 hugetlbfs_vfsmount = vfsmount;
1031                 return 0;
1032         }
1033
1034         error = PTR_ERR(vfsmount);
1035
1036  out:
1037         kmem_cache_destroy(hugetlbfs_inode_cachep);
1038  out2:
1039         bdi_destroy(&hugetlbfs_backing_dev_info);
1040         return error;
1041 }
1042
1043 static void __exit exit_hugetlbfs_fs(void)
1044 {
1045         kmem_cache_destroy(hugetlbfs_inode_cachep);
1046         kern_unmount(hugetlbfs_vfsmount);
1047         unregister_filesystem(&hugetlbfs_fs_type);
1048         bdi_destroy(&hugetlbfs_backing_dev_info);
1049 }
1050
1051 module_init(init_hugetlbfs_fs)
1052 module_exit(exit_hugetlbfs_fs)
1053
1054 MODULE_LICENSE("GPL");