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