fs/hugetlbfs/inode.c

   1 /*
   2  * hugetlbpage-backed filesystem.  Based on ramfs.
   3  *
   4  * William Irwin, 2002
   5  *
   6  * Copyright (C) 2002 Linus Torvalds.
   7  */
   8
   9 #include <linux/module.h>
  10 #include <linux/thread_info.h>
  11 #include <asm/current.h>
  12 #include <linux/sched.h>                /* remove ASAP */
  13 #include <linux/fs.h>
  14 #include <linux/mount.h>
  15 #include <linux/file.h>
  16 #include <linux/kernel.h>
  17 #include <linux/writeback.h>
  18 #include <linux/pagemap.h>
  19 #include <linux/highmem.h>
  20 #include <linux/init.h>
  21 #include <linux/string.h>
  22 #include <linux/capability.h>
  23 #include <linux/ctype.h>
  24 #include <linux/backing-dev.h>
  25 #include <linux/hugetlb.h>
  26 #include <linux/pagevec.h>
  27 #include <linux/parser.h>
  28 #include <linux/mman.h>
  29 #include <linux/quotaops.h>
  30 #include <linux/slab.h>
  31 #include <linux/dnotify.h>
  32 #include <linux/statfs.h>
  33 #include <linux/security.h>
  34
  35 #include <asm/uaccess.h>
  36
  37 /* some random number */
  38 #define HUGETLBFS_MAGIC 0x958458f6
  39
  40 static const struct super_operations hugetlbfs_ops;
  41 static const struct address_space_operations hugetlbfs_aops;
  42 const struct file_operations hugetlbfs_file_operations;
  43 static const struct inode_operations hugetlbfs_dir_inode_operations;
  44 static const struct inode_operations hugetlbfs_inode_operations;
  45
  46 static struct backing_dev_info hugetlbfs_backing_dev_info = {
  47         .ra_pages       = 0,    /* No readahead */
  48         .capabilities   = BDI_CAP_NO_ACCT_AND_WRITEBACK,
  49 };
  50
  51 int sysctl_hugetlb_shm_group;
  52
  53 enum {
  54         Opt_size, Opt_nr_inodes,
  55         Opt_mode, Opt_uid, Opt_gid,
  56         Opt_pagesize,
  57         Opt_err,
  58 };
  59
  60 static const match_table_t tokens = {
  61         {Opt_size,      "size=%s"},
  62         {Opt_nr_inodes, "nr_inodes=%s"},
  63         {Opt_mode,      "mode=%o"},
  64         {Opt_uid,       "uid=%u"},
  65         {Opt_gid,       "gid=%u"},
  66         {Opt_pagesize,  "pagesize=%s"},
  67         {Opt_err,       NULL},
  68 };
  69
  70 static void huge_pagevec_release(struct pagevec *pvec)
  71 {
  72         int i;
  73
  74         for (i = 0; i < pagevec_count(pvec); ++i)
  75                 put_page(pvec->pages[i]);
  76
  77         pagevec_reinit(pvec);
  78 }
  79
  80 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
  81 {
  82         struct inode *inode = file->f_path.dentry->d_inode;
  83         loff_t len, vma_len;
  84         int ret;
  85         struct hstate *h = hstate_file(file);
  86
  87         /*
  88          * vma address alignment (but not the pgoff alignment) has
  89          * already been checked by prepare_hugepage_range.  If you add
  90          * any error returns here, do so after setting VM_HUGETLB, so
  91          * is_vm_hugetlb_page tests below unmap_region go the right
  92          * way when do_mmap_pgoff unwinds (may be important on powerpc
  93          * and ia64).
  94          */
  95         vma->vm_flags |= VM_HUGETLB | VM_RESERVED;
  96         vma->vm_ops = &hugetlb_vm_ops;
  97
  98         if (vma->vm_pgoff & ~(huge_page_mask(h) >> PAGE_SHIFT))
  99                 return -EINVAL;
 100
 101         vma_len = (loff_t)(vma->vm_end - vma->vm_start);
 102
 103         mutex_lock(&inode->i_mutex);
 104         file_accessed(file);
 105
 106         ret = -ENOMEM;
 107         len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
 108
 109         if (hugetlb_reserve_pages(inode,
 110                                 vma->vm_pgoff >> huge_page_order(h),
 111                                 len >> huge_page_shift(h), vma,
 112                                 vma->vm_flags))
 113                 goto out;
 114
 115         ret = 0;
 116         hugetlb_prefault_arch_hook(vma->vm_mm);
 117         if (vma->vm_flags & VM_WRITE && inode->i_size < len)
 118                 inode->i_size = len;
 119 out:
 120         mutex_unlock(&inode->i_mutex);
 121
 122         return ret;
 123 }
 124
 125 /*
 126  * Called under down_write(mmap_sem).
 127  */
 128
 129 #ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
 130 static unsigned long
 131 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 132                 unsigned long len, unsigned long pgoff, unsigned long flags)
 133 {
 134         struct mm_struct *mm = current->mm;
 135         struct vm_area_struct *vma;
 136         unsigned long start_addr;
 137         struct hstate *h = hstate_file(file);
 138
 139         if (len & ~huge_page_mask(h))
 140                 return -EINVAL;
 141         if (len > TASK_SIZE)
 142                 return -ENOMEM;
 143
 144         if (flags & MAP_FIXED) {
 145                 if (prepare_hugepage_range(file, addr, len))
 146                         return -EINVAL;
 147                 return addr;
 148         }
 149
 150         if (addr) {
 151                 addr = ALIGN(addr, huge_page_size(h));
 152                 vma = find_vma(mm, addr);
 153                 if (TASK_SIZE - len >= addr &&
 154                     (!vma || addr + len <= vma->vm_start))
 155                         return addr;
 156         }
 157
 158         start_addr = mm->free_area_cache;
 159
 160         if (len <= mm->cached_hole_size)
 161                 start_addr = TASK_UNMAPPED_BASE;
 162
 163 full_search:
 164         addr = ALIGN(start_addr, huge_page_size(h));
 165
 166         for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
 167                 /* At this point:  (!vma || addr < vma->vm_end). */
 168                 if (TASK_SIZE - len < addr) {
 169                         /*
 170                          * Start a new search - just in case we missed
 171                          * some holes.
 172                          */
 173                         if (start_addr != TASK_UNMAPPED_BASE) {
 174                                 start_addr = TASK_UNMAPPED_BASE;
 175                                 goto full_search;
 176                         }
 177                         return -ENOMEM;
 178                 }
 179
 180                 if (!vma || addr + len <= vma->vm_start)
 181                         return addr;
 182                 addr = ALIGN(vma->vm_end, huge_page_size(h));
 183         }
 184 }
 185 #endif
 186
 187 static int
 188 hugetlbfs_read_actor(struct page *page, unsigned long offset,
 189                         char __user *buf, unsigned long count,
 190                         unsigned long size)
 191 {
 192         char *kaddr;
 193         unsigned long left, copied = 0;
 194         int i, chunksize;
 195
 196         if (size > count)
 197                 size = count;
 198
 199         /* Find which 4k chunk and offset with in that chunk */
 200         i = offset >> PAGE_CACHE_SHIFT;
 201         offset = offset & ~PAGE_CACHE_MASK;
 202
 203         while (size) {
 204                 chunksize = PAGE_CACHE_SIZE;
 205                 if (offset)
 206                         chunksize -= offset;
 207                 if (chunksize > size)
 208                         chunksize = size;
 209                 kaddr = kmap(&page[i]);
 210                 left = __copy_to_user(buf, kaddr + offset, chunksize);
 211                 kunmap(&page[i]);
 212                 if (left) {
 213                         copied += (chunksize - left);
 214                         break;
 215                 }
 216                 offset = 0;
 217                 size -= chunksize;
 218                 buf += chunksize;
 219                 copied += chunksize;
 220                 i++;
 221         }
 222         return copied ? copied : -EFAULT;
 223 }
 224
 225 /*
 226  * Support for read() - Find the page attached to f_mapping and copy out the
 227  * data. Its *very* similar to do_generic_mapping_read(), we can't use that
 228  * since it has PAGE_CACHE_SIZE assumptions.
 229  */
 230 static ssize_t hugetlbfs_read(struct file *filp, char __user *buf,
 231                               size_t len, loff_t *ppos)
 232 {
 233         struct hstate *h = hstate_file(filp);
 234         struct address_space *mapping = filp->f_mapping;
 235         struct inode *inode = mapping->host;
 236         unsigned long index = *ppos >> huge_page_shift(h);
 237         unsigned long offset = *ppos & ~huge_page_mask(h);
 238         unsigned long end_index;
 239         loff_t isize;
 240         ssize_t retval = 0;
 241
 242         mutex_lock(&inode->i_mutex);
 243
 244         /* validate length */
 245         if (len == 0)
 246                 goto out;
 247
 248         isize = i_size_read(inode);
 249         if (!isize)
 250                 goto out;
 251
 252         end_index = (isize - 1) >> huge_page_shift(h);
 253         for (;;) {
 254                 struct page *page;
 255                 unsigned long nr, ret;
 256                 int ra;
 257
 258                 /* nr is the maximum number of bytes to copy from this page */
 259                 nr = huge_page_size(h);
 260                 if (index >= end_index) {
 261                         if (index > end_index)
 262                                 goto out;
 263                         nr = ((isize - 1) & ~huge_page_mask(h)) + 1;
 264                         if (nr <= offset) {
 265                                 goto out;
 266                         }
 267                 }
 268                 nr = nr - offset;
 269
 270                 /* Find the page */
 271                 page = find_get_page(mapping, index);
 272                 if (unlikely(page == NULL)) {
 273                         /*
 274                          * We have a HOLE, zero out the user-buffer for the
 275                          * length of the hole or request.
 276                          */
 277                         ret = len < nr ? len : nr;
 278                         if (clear_user(buf, ret))
 279                                 ra = -EFAULT;
 280                         else
 281                                 ra = 0;
 282                 } else {
 283                         /*
 284                          * We have the page, copy it to user space buffer.
 285                          */
 286                         ra = hugetlbfs_read_actor(page, offset, buf, len, nr);
 287                         ret = ra;
 288                 }
 289                 if (ra < 0) {
 290                         if (retval == 0)
 291                                 retval = ra;
 292                         if (page)
 293                                 page_cache_release(page);
 294                         goto out;
 295                 }
 296
 297                 offset += ret;
 298                 retval += ret;
 299                 len -= ret;
 300                 index += offset >> huge_page_shift(h);
 301                 offset &= ~huge_page_mask(h);
 302
 303                 if (page)
 304                         page_cache_release(page);
 305
 306                 /* short read or no more work */
 307                 if ((ret != nr) || (len == 0))
 308                         break;
 309         }
 310 out:
 311         *ppos = ((loff_t)index << huge_page_shift(h)) + offset;
 312         mutex_unlock(&inode->i_mutex);
 313         return retval;
 314 }
 315
 316 /*
 317  * Read a page. Again trivial. If it didn't already exist
 318  * in the page cache, it is zero-filled.
 319  */
 320 static int hugetlbfs_readpage(struct file *file, struct page * page)
 321 {
 322         unlock_page(page);
 323         return -EINVAL;
 324 }
 325
 326 static int hugetlbfs_write_begin(struct file *file,
 327                         struct address_space *mapping,
 328                         loff_t pos, unsigned len, unsigned flags,
 329                         struct page **pagep, void **fsdata)
 330 {
 331         return -EINVAL;
 332 }
 333
 334 static int hugetlbfs_write_end(struct file *file, struct address_space *mapping,
 335                         loff_t pos, unsigned len, unsigned copied,
 336                         struct page *page, void *fsdata)
 337 {
 338         BUG();
 339         return -EINVAL;
 340 }
 341
 342 static void truncate_huge_page(struct page *page)
 343 {
 344         cancel_dirty_page(page, /* No IO accounting for huge pages? */0);
 345         ClearPageUptodate(page);
 346         remove_from_page_cache(page);
 347         put_page(page);
 348 }
 349
 350 static void truncate_hugepages(struct inode *inode, loff_t lstart)
 351 {
 352         struct hstate *h = hstate_inode(inode);
 353         struct address_space *mapping = &inode->i_data;
 354         const pgoff_t start = lstart >> huge_page_shift(h);
 355         struct pagevec pvec;
 356         pgoff_t next;
 357         int i, freed = 0;
 358
 359         pagevec_init(&pvec, 0);
 360         next = start;
 361         while (1) {
 362                 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
 363                         if (next == start)
 364                                 break;
 365                         next = start;
 366                         continue;
 367                 }
 368
 369                 for (i = 0; i < pagevec_count(&pvec); ++i) {
 370                         struct page *page = pvec.pages[i];
 371
 372                         lock_page(page);
 373                         if (page->index > next)
 374                                 next = page->index;
 375                         ++next;
 376                         truncate_huge_page(page);
 377                         unlock_page(page);
 378                         freed++;
 379                 }
 380                 huge_pagevec_release(&pvec);
 381         }
 382         BUG_ON(!lstart && mapping->nrpages);
 383         hugetlb_unreserve_pages(inode, start, freed);
 384 }
 385
 386 static void hugetlbfs_delete_inode(struct inode *inode)
 387 {
 388         truncate_hugepages(inode, 0);
 389         clear_inode(inode);
 390 }
 391
 392 static void hugetlbfs_forget_inode(struct inode *inode) __releases(inode_lock)
 393 {
 394         struct super_block *sb = inode->i_sb;
 395
 396         if (!hlist_unhashed(&inode->i_hash)) {
 397                 if (!(inode->i_state & (I_DIRTY|I_SYNC)))
 398                         list_move(&inode->i_list, &inode_unused);
 399                 inodes_stat.nr_unused++;
 400                 if (!sb || (sb->s_flags & MS_ACTIVE)) {
 401                         spin_unlock(&inode_lock);
 402                         return;
 403                 }
 404                 inode->i_state |= I_WILL_FREE;
 405                 spin_unlock(&inode_lock);
 406                 /*
 407                  * write_inode_now is a noop as we set BDI_CAP_NO_WRITEBACK
 408                  * in our backing_dev_info.
 409                  */
 410                 write_inode_now(inode, 1);
 411                 spin_lock(&inode_lock);
 412                 inode->i_state &= ~I_WILL_FREE;
 413                 inodes_stat.nr_unused--;
 414                 hlist_del_init(&inode->i_hash);
 415         }
 416         list_del_init(&inode->i_list);
 417         list_del_init(&inode->i_sb_list);
 418         inode->i_state |= I_FREEING;
 419         inodes_stat.nr_inodes--;
 420         spin_unlock(&inode_lock);
 421         truncate_hugepages(inode, 0);
 422         clear_inode(inode);
 423         destroy_inode(inode);
 424 }
 425
 426 static void hugetlbfs_drop_inode(struct inode *inode)
 427 {
 428         if (!inode->i_nlink)
 429                 generic_delete_inode(inode);
 430         else
 431                 hugetlbfs_forget_inode(inode);
 432 }
 433
 434 static inline void
 435 hugetlb_vmtruncate_list(struct prio_tree_root *root, pgoff_t pgoff)
 436 {
 437         struct vm_area_struct *vma;
 438         struct prio_tree_iter iter;
 439
 440         vma_prio_tree_foreach(vma, &iter, root, pgoff, ULONG_MAX) {
 441                 unsigned long v_offset;
 442
 443                 /*
 444                  * Can the expression below overflow on 32-bit arches?
 445                  * No, because the prio_tree returns us only those vmas
 446                  * which overlap the truncated area starting at pgoff,
 447                  * and no vma on a 32-bit arch can span beyond the 4GB.
 448                  */
 449                 if (vma->vm_pgoff < pgoff)
 450                         v_offset = (pgoff - vma->vm_pgoff) << PAGE_SHIFT;
 451                 else
 452                         v_offset = 0;
 453
 454                 __unmap_hugepage_range(vma,
 455                                 vma->vm_start + v_offset, vma->vm_end, NULL);
 456         }
 457 }
 458
 459 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
 460 {
 461         pgoff_t pgoff;
 462         struct address_space *mapping = inode->i_mapping;
 463         struct hstate *h = hstate_inode(inode);
 464
 465         BUG_ON(offset & ~huge_page_mask(h));
 466         pgoff = offset >> PAGE_SHIFT;
 467
 468         i_size_write(inode, offset);
 469         spin_lock(&mapping->i_mmap_lock);
 470         if (!prio_tree_empty(&mapping->i_mmap))
 471                 hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff);
 472         spin_unlock(&mapping->i_mmap_lock);
 473         truncate_hugepages(inode, offset);
 474         return 0;
 475 }
 476
 477 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
 478 {
 479         struct inode *inode = dentry->d_inode;
 480         struct hstate *h = hstate_inode(inode);
 481         int error;
 482         unsigned int ia_valid = attr->ia_valid;
 483
 484         BUG_ON(!inode);
 485
 486         error = inode_change_ok(inode, attr);
 487         if (error)
 488                 goto out;
 489
 490         if (ia_valid & ATTR_SIZE) {
 491                 error = -EINVAL;
 492                 if (!(attr->ia_size & ~huge_page_mask(h)))
 493                         error = hugetlb_vmtruncate(inode, attr->ia_size);
 494                 if (error)
 495                         goto out;
 496                 attr->ia_valid &= ~ATTR_SIZE;
 497         }
 498         error = inode_setattr(inode, attr);
 499 out:
 500         return error;
 501 }
 502
 503 static struct inode *hugetlbfs_get_inode(struct super_block *sb, uid_t uid,
 504                                         gid_t gid, int mode, dev_t dev)
 505 {
 506         struct inode *inode;
 507
 508         inode = new_inode(sb);
 509         if (inode) {
 510                 struct hugetlbfs_inode_info *info;
 511                 inode->i_mode = mode;
 512                 inode->i_uid = uid;
 513                 inode->i_gid = gid;
 514                 inode->i_mapping->a_ops = &hugetlbfs_aops;
 515                 inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info;
 516                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 517                 INIT_LIST_HEAD(&inode->i_mapping->private_list);
 518                 info = HUGETLBFS_I(inode);
 519                 mpol_shared_policy_init(&info->policy, NULL);
 520                 switch (mode & S_IFMT) {
 521                 default:
 522                         init_special_inode(inode, mode, dev);
 523                         break;
 524                 case S_IFREG:
 525                         inode->i_op = &hugetlbfs_inode_operations;
 526                         inode->i_fop = &hugetlbfs_file_operations;
 527                         break;
 528                 case S_IFDIR:
 529                         inode->i_op = &hugetlbfs_dir_inode_operations;
 530                         inode->i_fop = &simple_dir_operations;
 531
 532                         /* directory inodes start off with i_nlink == 2 (for "." entry) */
 533                         inc_nlink(inode);
 534                         break;
 535                 case S_IFLNK:
 536                         inode->i_op = &page_symlink_inode_operations;
 537                         break;
 538                 }
 539         }
 540         return inode;
 541 }
 542
 543 /*
 544  * File creation. Allocate an inode, and we're done..
 545  */
 546 static int hugetlbfs_mknod(struct inode *dir,
 547                         struct dentry *dentry, int mode, dev_t dev)
 548 {
 549         struct inode *inode;
 550         int error = -ENOSPC;
 551         gid_t gid;
 552
 553         if (dir->i_mode & S_ISGID) {
 554                 gid = dir->i_gid;
 555                 if (S_ISDIR(mode))
 556                         mode |= S_ISGID;
 557         } else {
 558                 gid = current_fsgid();
 559         }
 560         inode = hugetlbfs_get_inode(dir->i_sb, current_fsuid(), gid, mode, dev);
 561         if (inode) {
 562                 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 563                 d_instantiate(dentry, inode);
 564                 dget(dentry);   /* Extra count - pin the dentry in core */
 565                 error = 0;
 566         }
 567         return error;
 568 }
 569
 570 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 571 {
 572         int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
 573         if (!retval)
 574                 inc_nlink(dir);
 575         return retval;
 576 }
 577
 578 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, int mode, struct nameidata *nd)
 579 {
 580         return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
 581 }
 582
 583 static int hugetlbfs_symlink(struct inode *dir,
 584                         struct dentry *dentry, const char *symname)
 585 {
 586         struct inode *inode;
 587         int error = -ENOSPC;
 588         gid_t gid;
 589
 590         if (dir->i_mode & S_ISGID)
 591                 gid = dir->i_gid;
 592         else
 593                 gid = current_fsgid();
 594
 595         inode = hugetlbfs_get_inode(dir->i_sb, current_fsuid(),
 596                                         gid, S_IFLNK|S_IRWXUGO, 0);
 597         if (inode) {
 598                 int l = strlen(symname)+1;
 599                 error = page_symlink(inode, symname, l);
 600                 if (!error) {
 601                         d_instantiate(dentry, inode);
 602                         dget(dentry);
 603                 } else
 604                         iput(inode);
 605         }
 606         dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 607
 608         return error;
 609 }
 610
 611 /*
 612  * mark the head page dirty
 613  */
 614 static int hugetlbfs_set_page_dirty(struct page *page)
 615 {
 616         struct page *head = compound_head(page);
 617
 618         SetPageDirty(head);
 619         return 0;
 620 }
 621
 622 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 623 {
 624         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
 625         struct hstate *h = hstate_inode(dentry->d_inode);
 626
 627         buf->f_type = HUGETLBFS_MAGIC;
 628         buf->f_bsize = huge_page_size(h);
 629         if (sbinfo) {
 630                 spin_lock(&sbinfo->stat_lock);
 631                 /* If no limits set, just report 0 for max/free/used
 632                  * blocks, like simple_statfs() */
 633                 if (sbinfo->max_blocks >= 0) {
 634                         buf->f_blocks = sbinfo->max_blocks;
 635                         buf->f_bavail = buf->f_bfree = sbinfo->free_blocks;
 636                         buf->f_files = sbinfo->max_inodes;
 637                         buf->f_ffree = sbinfo->free_inodes;
 638                 }
 639                 spin_unlock(&sbinfo->stat_lock);
 640         }
 641         buf->f_namelen = NAME_MAX;
 642         return 0;
 643 }
 644
 645 static void hugetlbfs_put_super(struct super_block *sb)
 646 {
 647         struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
 648
 649         if (sbi) {
 650                 sb->s_fs_info = NULL;
 651                 kfree(sbi);
 652         }
 653 }
 654
 655 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
 656 {
 657         if (sbinfo->free_inodes >= 0) {
 658                 spin_lock(&sbinfo->stat_lock);
 659                 if (unlikely(!sbinfo->free_inodes)) {
 660                         spin_unlock(&sbinfo->stat_lock);
 661                         return 0;
 662                 }
 663                 sbinfo->free_inodes--;
 664                 spin_unlock(&sbinfo->stat_lock);
 665         }
 666
 667         return 1;
 668 }
 669
 670 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
 671 {
 672         if (sbinfo->free_inodes >= 0) {
 673                 spin_lock(&sbinfo->stat_lock);
 674                 sbinfo->free_inodes++;
 675                 spin_unlock(&sbinfo->stat_lock);
 676         }
 677 }
 678
 679
 680 static struct kmem_cache *hugetlbfs_inode_cachep;
 681
 682 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
 683 {
 684         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
 685         struct hugetlbfs_inode_info *p;
 686
 687         if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
 688                 return NULL;
 689         p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL);
 690         if (unlikely(!p)) {
 691                 hugetlbfs_inc_free_inodes(sbinfo);
 692                 return NULL;
 693         }
 694         return &p->vfs_inode;
 695 }
 696
 697 static void hugetlbfs_destroy_inode(struct inode *inode)
 698 {
 699         hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
 700         mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
 701         kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
 702 }
 703
 704 static const struct address_space_operations hugetlbfs_aops = {
 705         .readpage       = hugetlbfs_readpage,
 706         .write_begin    = hugetlbfs_write_begin,
 707         .write_end      = hugetlbfs_write_end,
 708         .set_page_dirty = hugetlbfs_set_page_dirty,
 709 };
 710
 711
 712 static void init_once(void *foo)
 713 {
 714         struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
 715
 716         inode_init_once(&ei->vfs_inode);
 717 }
 718
 719 const struct file_operations hugetlbfs_file_operations = {
 720         .read                   = hugetlbfs_read,
 721         .mmap                   = hugetlbfs_file_mmap,
 722         .fsync                  = simple_sync_file,
 723         .get_unmapped_area      = hugetlb_get_unmapped_area,
 724 };
 725
 726 static const struct inode_operations hugetlbfs_dir_inode_operations = {
 727         .create         = hugetlbfs_create,
 728         .lookup         = simple_lookup,
 729         .link           = simple_link,
 730         .unlink         = simple_unlink,
 731         .symlink        = hugetlbfs_symlink,
 732         .mkdir          = hugetlbfs_mkdir,
 733         .rmdir          = simple_rmdir,
 734         .mknod          = hugetlbfs_mknod,
 735         .rename         = simple_rename,
 736         .setattr        = hugetlbfs_setattr,
 737 };
 738
 739 static const struct inode_operations hugetlbfs_inode_operations = {
 740         .setattr        = hugetlbfs_setattr,
 741 };
 742
 743 static const struct super_operations hugetlbfs_ops = {
 744         .alloc_inode    = hugetlbfs_alloc_inode,
 745         .destroy_inode  = hugetlbfs_destroy_inode,
 746         .statfs         = hugetlbfs_statfs,
 747         .delete_inode   = hugetlbfs_delete_inode,
 748         .drop_inode     = hugetlbfs_drop_inode,
 749         .put_super      = hugetlbfs_put_super,
 750         .show_options   = generic_show_options,
 751 };
 752
 753 static int
 754 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
 755 {
 756         char *p, *rest;
 757         substring_t args[MAX_OPT_ARGS];
 758         int option;
 759         unsigned long long size = 0;
 760         enum { NO_SIZE, SIZE_STD, SIZE_PERCENT } setsize = NO_SIZE;
 761
 762         if (!options)
 763                 return 0;
 764
 765         while ((p = strsep(&options, ",")) != NULL) {
 766                 int token;
 767                 if (!*p)
 768                         continue;
 769
 770                 token = match_token(p, tokens, args);
 771                 switch (token) {
 772                 case Opt_uid:
 773                         if (match_int(&args[0], &option))
 774                                 goto bad_val;
 775                         pconfig->uid = option;
 776                         break;
 777
 778                 case Opt_gid:
 779                         if (match_int(&args[0], &option))
 780                                 goto bad_val;
 781                         pconfig->gid = option;
 782                         break;
 783
 784                 case Opt_mode:
 785                         if (match_octal(&args[0], &option))
 786                                 goto bad_val;
 787                         pconfig->mode = option & 01777U;
 788                         break;
 789
 790                 case Opt_size: {
 791                         /* memparse() will accept a K/M/G without a digit */
 792                         if (!isdigit(*args[0].from))
 793                                 goto bad_val;
 794                         size = memparse(args[0].from, &rest);
 795                         setsize = SIZE_STD;
 796                         if (*rest == '%')
 797                                 setsize = SIZE_PERCENT;
 798                         break;
 799                 }
 800
 801                 case Opt_nr_inodes:
 802                         /* memparse() will accept a K/M/G without a digit */
 803                         if (!isdigit(*args[0].from))
 804                                 goto bad_val;
 805                         pconfig->nr_inodes = memparse(args[0].from, &rest);
 806                         break;
 807
 808                 case Opt_pagesize: {
 809                         unsigned long ps;
 810                         ps = memparse(args[0].from, &rest);
 811                         pconfig->hstate = size_to_hstate(ps);
 812                         if (!pconfig->hstate) {
 813                                 printk(KERN_ERR
 814                                 "hugetlbfs: Unsupported page size %lu MB\n",
 815                                         ps >> 20);
 816                                 return -EINVAL;
 817                         }
 818                         break;
 819                 }
 820
 821                 default:
 822                         printk(KERN_ERR "hugetlbfs: Bad mount option: \"%s\"\n",
 823                                  p);
 824                         return -EINVAL;
 825                         break;
 826                 }
 827         }
 828
 829         /* Do size after hstate is set up */
 830         if (setsize > NO_SIZE) {
 831                 struct hstate *h = pconfig->hstate;
 832                 if (setsize == SIZE_PERCENT) {
 833                         size <<= huge_page_shift(h);
 834                         size *= h->max_huge_pages;
 835                         do_div(size, 100);
 836                 }
 837                 pconfig->nr_blocks = (size >> huge_page_shift(h));
 838         }
 839
 840         return 0;
 841
 842 bad_val:
 843         printk(KERN_ERR "hugetlbfs: Bad value '%s' for mount option '%s'\n",
 844                args[0].from, p);
 845         return 1;
 846 }
 847
 848 static int
 849 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
 850 {
 851         struct inode * inode;
 852         struct dentry * root;
 853         int ret;
 854         struct hugetlbfs_config config;
 855         struct hugetlbfs_sb_info *sbinfo;
 856
 857         save_mount_options(sb, data);
 858
 859         config.nr_blocks = -1; /* No limit on size by default */
 860         config.nr_inodes = -1; /* No limit on number of inodes by default */
 861         config.uid = current_fsuid();
 862         config.gid = current_fsgid();
 863         config.mode = 0755;
 864         config.hstate = &default_hstate;
 865         ret = hugetlbfs_parse_options(data, &config);
 866         if (ret)
 867                 return ret;
 868
 869         sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
 870         if (!sbinfo)
 871                 return -ENOMEM;
 872         sb->s_fs_info = sbinfo;
 873         sbinfo->hstate = config.hstate;
 874         spin_lock_init(&sbinfo->stat_lock);
 875         sbinfo->max_blocks = config.nr_blocks;
 876         sbinfo->free_blocks = config.nr_blocks;
 877         sbinfo->max_inodes = config.nr_inodes;
 878         sbinfo->free_inodes = config.nr_inodes;
 879         sb->s_maxbytes = MAX_LFS_FILESIZE;
 880         sb->s_blocksize = huge_page_size(config.hstate);
 881         sb->s_blocksize_bits = huge_page_shift(config.hstate);
 882         sb->s_magic = HUGETLBFS_MAGIC;
 883         sb->s_op = &hugetlbfs_ops;
 884         sb->s_time_gran = 1;
 885         inode = hugetlbfs_get_inode(sb, config.uid, config.gid,
 886                                         S_IFDIR | config.mode, 0);
 887         if (!inode)
 888                 goto out_free;
 889
 890         root = d_alloc_root(inode);
 891         if (!root) {
 892                 iput(inode);
 893                 goto out_free;
 894         }
 895         sb->s_root = root;
 896         return 0;
 897 out_free:
 898         kfree(sbinfo);
 899         return -ENOMEM;
 900 }
 901
 902 int hugetlb_get_quota(struct address_space *mapping, long delta)
 903 {
 904         int ret = 0;
 905         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
 906
 907         if (sbinfo->free_blocks > -1) {
 908                 spin_lock(&sbinfo->stat_lock);
 909                 if (sbinfo->free_blocks - delta >= 0)
 910                         sbinfo->free_blocks -= delta;
 911                 else
 912                         ret = -ENOMEM;
 913                 spin_unlock(&sbinfo->stat_lock);
 914         }
 915
 916         return ret;
 917 }
 918
 919 void hugetlb_put_quota(struct address_space *mapping, long delta)
 920 {
 921         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
 922
 923         if (sbinfo->free_blocks > -1) {
 924                 spin_lock(&sbinfo->stat_lock);
 925                 sbinfo->free_blocks += delta;
 926                 spin_unlock(&sbinfo->stat_lock);
 927         }
 928 }
 929
 930 static int hugetlbfs_get_sb(struct file_system_type *fs_type,
 931         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
 932 {
 933         return get_sb_nodev(fs_type, flags, data, hugetlbfs_fill_super, mnt);
 934 }
 935
 936 static struct file_system_type hugetlbfs_fs_type = {
 937         .name           = "hugetlbfs",
 938         .get_sb         = hugetlbfs_get_sb,
 939         .kill_sb        = kill_litter_super,
 940 };
 941
 942 static struct vfsmount *hugetlbfs_vfsmount;
 943
 944 static int can_do_hugetlb_shm(void)
 945 {
 946         return capable(CAP_IPC_LOCK) || in_group_p(sysctl_hugetlb_shm_group);
 947 }
 948
 949 struct file *hugetlb_file_setup(const char *name, size_t size, int acctflag)
 950 {
 951         int error = -ENOMEM;
 952         int unlock_shm = 0;
 953         struct file *file;
 954         struct inode *inode;
 955         struct dentry *dentry, *root;
 956         struct qstr quick_string;
 957         struct user_struct *user = current_user();
 958
 959         if (!hugetlbfs_vfsmount)
 960                 return ERR_PTR(-ENOENT);
 961
 962         if (!can_do_hugetlb_shm()) {
 963                 if (user_shm_lock(size, user)) {
 964                         unlock_shm = 1;
 965                         WARN_ONCE(1,
 966                           "Using mlock ulimits for SHM_HUGETLB deprecated\n");
 967                 } else
 968                         return ERR_PTR(-EPERM);
 969         }
 970
 971         root = hugetlbfs_vfsmount->mnt_root;
 972         quick_string.name = name;
 973         quick_string.len = strlen(quick_string.name);
 974         quick_string.hash = 0;
 975         dentry = d_alloc(root, &quick_string);
 976         if (!dentry)
 977                 goto out_shm_unlock;
 978
 979         error = -ENOSPC;
 980         inode = hugetlbfs_get_inode(root->d_sb, current_fsuid(),
 981                                 current_fsgid(), S_IFREG | S_IRWXUGO, 0);
 982         if (!inode)
 983                 goto out_dentry;
 984
 985         error = -ENOMEM;
 986         if (hugetlb_reserve_pages(inode, 0,
 987                         size >> huge_page_shift(hstate_inode(inode)), NULL,
 988                         acctflag))
 989                 goto out_inode;
 990
 991         d_instantiate(dentry, inode);
 992         inode->i_size = size;
 993         inode->i_nlink = 0;
 994
 995         error = -ENFILE;
 996         file = alloc_file(hugetlbfs_vfsmount, dentry,
 997                         FMODE_WRITE | FMODE_READ,
 998                         &hugetlbfs_file_operations);
 999         if (!file)
1000                 goto out_dentry; /* inode is already attached */
1001
1002         return file;
1003
1004 out_inode:
1005         iput(inode);
1006 out_dentry:
1007         dput(dentry);
1008 out_shm_unlock:
1009         if (unlock_shm)
1010                 user_shm_unlock(size, user);
1011         return ERR_PTR(error);
1012 }
1013
1014 static int __init init_hugetlbfs_fs(void)
1015 {
1016         int error;
1017         struct vfsmount *vfsmount;
1018
1019         error = bdi_init(&hugetlbfs_backing_dev_info);
1020         if (error)
1021                 return error;
1022
1023         hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
1024                                         sizeof(struct hugetlbfs_inode_info),
1025                                         0, 0, init_once);
1026         if (hugetlbfs_inode_cachep == NULL)
1027                 goto out2;
1028
1029         error = register_filesystem(&hugetlbfs_fs_type);
1030         if (error)
1031                 goto out;
1032
1033         vfsmount = kern_mount(&hugetlbfs_fs_type);
1034
1035         if (!IS_ERR(vfsmount)) {
1036                 hugetlbfs_vfsmount = vfsmount;
1037                 return 0;
1038         }
1039
1040         error = PTR_ERR(vfsmount);
1041
1042  out:
1043         if (error)
1044                 kmem_cache_destroy(hugetlbfs_inode_cachep);
1045  out2:
1046         bdi_destroy(&hugetlbfs_backing_dev_info);
1047         return error;
1048 }
1049
1050 static void __exit exit_hugetlbfs_fs(void)
1051 {
1052         kmem_cache_destroy(hugetlbfs_inode_cachep);
1053         unregister_filesystem(&hugetlbfs_fs_type);
1054         bdi_destroy(&hugetlbfs_backing_dev_info);
1055 }
1056
1057 module_init(init_hugetlbfs_fs)
1058 module_exit(exit_hugetlbfs_fs)
1059
1060 MODULE_LICENSE("GPL");