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         kuid_t   uid;
  46         kgid_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_DONTEXPAND | VM_DONTDUMP;
 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 rb_root *root, pgoff_t pgoff)
 401 {
 402         struct vm_area_struct *vma;
 403
 404         vma_interval_tree_foreach(vma, root, pgoff, ULONG_MAX) {
 405                 unsigned long v_offset;
 406
 407                 /*
 408                  * Can the expression below overflow on 32-bit arches?
 409                  * No, because the interval tree returns us only those vmas
 410                  * which overlap the truncated area starting at pgoff,
 411                  * and no vma on a 32-bit arch can span beyond the 4GB.
 412                  */
 413                 if (vma->vm_pgoff < pgoff)
 414                         v_offset = (pgoff - vma->vm_pgoff) << PAGE_SHIFT;
 415                 else
 416                         v_offset = 0;
 417
 418                 unmap_hugepage_range(vma, vma->vm_start + v_offset,
 419                                      vma->vm_end, NULL);
 420         }
 421 }
 422
 423 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
 424 {
 425         pgoff_t pgoff;
 426         struct address_space *mapping = inode->i_mapping;
 427         struct hstate *h = hstate_inode(inode);
 428
 429         BUG_ON(offset & ~huge_page_mask(h));
 430         pgoff = offset >> PAGE_SHIFT;
 431
 432         i_size_write(inode, offset);
 433         mutex_lock(&mapping->i_mmap_mutex);
 434         if (!RB_EMPTY_ROOT(&mapping->i_mmap))
 435                 hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff);
 436         mutex_unlock(&mapping->i_mmap_mutex);
 437         truncate_hugepages(inode, offset);
 438         return 0;
 439 }
 440
 441 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
 442 {
 443         struct inode *inode = dentry->d_inode;
 444         struct hstate *h = hstate_inode(inode);
 445         int error;
 446         unsigned int ia_valid = attr->ia_valid;
 447
 448         BUG_ON(!inode);
 449
 450         error = inode_change_ok(inode, attr);
 451         if (error)
 452                 return error;
 453
 454         if (ia_valid & ATTR_SIZE) {
 455                 error = -EINVAL;
 456                 if (attr->ia_size & ~huge_page_mask(h))
 457                         return -EINVAL;
 458                 error = hugetlb_vmtruncate(inode, attr->ia_size);
 459                 if (error)
 460                         return error;
 461         }
 462
 463         setattr_copy(inode, attr);
 464         mark_inode_dirty(inode);
 465         return 0;
 466 }
 467
 468 static struct inode *hugetlbfs_get_root(struct super_block *sb,
 469                                         struct hugetlbfs_config *config)
 470 {
 471         struct inode *inode;
 472
 473         inode = new_inode(sb);
 474         if (inode) {
 475                 struct hugetlbfs_inode_info *info;
 476                 inode->i_ino = get_next_ino();
 477                 inode->i_mode = S_IFDIR | config->mode;
 478                 inode->i_uid = config->uid;
 479                 inode->i_gid = config->gid;
 480                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 481                 info = HUGETLBFS_I(inode);
 482                 mpol_shared_policy_init(&info->policy, NULL);
 483                 inode->i_op = &hugetlbfs_dir_inode_operations;
 484                 inode->i_fop = &simple_dir_operations;
 485                 /* directory inodes start off with i_nlink == 2 (for "." entry) */
 486                 inc_nlink(inode);
 487                 lockdep_annotate_inode_mutex_key(inode);
 488         }
 489         return inode;
 490 }
 491
 492 static struct inode *hugetlbfs_get_inode(struct super_block *sb,
 493                                         struct inode *dir,
 494                                         umode_t mode, dev_t dev)
 495 {
 496         struct inode *inode;
 497
 498         inode = new_inode(sb);
 499         if (inode) {
 500                 struct hugetlbfs_inode_info *info;
 501                 inode->i_ino = get_next_ino();
 502                 inode_init_owner(inode, dir, mode);
 503                 inode->i_mapping->a_ops = &hugetlbfs_aops;
 504                 inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info;
 505                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 506                 INIT_LIST_HEAD(&inode->i_mapping->private_list);
 507                 info = HUGETLBFS_I(inode);
 508                 /*
 509                  * The policy is initialized here even if we are creating a
 510                  * private inode because initialization simply creates an
 511                  * an empty rb tree and calls spin_lock_init(), later when we
 512                  * call mpol_free_shared_policy() it will just return because
 513                  * the rb tree will still be empty.
 514                  */
 515                 mpol_shared_policy_init(&info->policy, NULL);
 516                 switch (mode & S_IFMT) {
 517                 default:
 518                         init_special_inode(inode, mode, dev);
 519                         break;
 520                 case S_IFREG:
 521                         inode->i_op = &hugetlbfs_inode_operations;
 522                         inode->i_fop = &hugetlbfs_file_operations;
 523                         break;
 524                 case S_IFDIR:
 525                         inode->i_op = &hugetlbfs_dir_inode_operations;
 526                         inode->i_fop = &simple_dir_operations;
 527
 528                         /* directory inodes start off with i_nlink == 2 (for "." entry) */
 529                         inc_nlink(inode);
 530                         break;
 531                 case S_IFLNK:
 532                         inode->i_op = &page_symlink_inode_operations;
 533                         break;
 534                 }
 535                 lockdep_annotate_inode_mutex_key(inode);
 536         }
 537         return inode;
 538 }
 539
 540 /*
 541  * File creation. Allocate an inode, and we're done..
 542  */
 543 static int hugetlbfs_mknod(struct inode *dir,
 544                         struct dentry *dentry, umode_t mode, dev_t dev)
 545 {
 546         struct inode *inode;
 547         int error = -ENOSPC;
 548
 549         inode = hugetlbfs_get_inode(dir->i_sb, dir, mode, dev);
 550         if (inode) {
 551                 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 552                 d_instantiate(dentry, inode);
 553                 dget(dentry);   /* Extra count - pin the dentry in core */
 554                 error = 0;
 555         }
 556         return error;
 557 }
 558
 559 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 560 {
 561         int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
 562         if (!retval)
 563                 inc_nlink(dir);
 564         return retval;
 565 }
 566
 567 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl)
 568 {
 569         return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
 570 }
 571
 572 static int hugetlbfs_symlink(struct inode *dir,
 573                         struct dentry *dentry, const char *symname)
 574 {
 575         struct inode *inode;
 576         int error = -ENOSPC;
 577
 578         inode = hugetlbfs_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0);
 579         if (inode) {
 580                 int l = strlen(symname)+1;
 581                 error = page_symlink(inode, symname, l);
 582                 if (!error) {
 583                         d_instantiate(dentry, inode);
 584                         dget(dentry);
 585                 } else
 586                         iput(inode);
 587         }
 588         dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 589
 590         return error;
 591 }
 592
 593 /*
 594  * mark the head page dirty
 595  */
 596 static int hugetlbfs_set_page_dirty(struct page *page)
 597 {
 598         struct page *head = compound_head(page);
 599
 600         SetPageDirty(head);
 601         return 0;
 602 }
 603
 604 static int hugetlbfs_migrate_page(struct address_space *mapping,
 605                                 struct page *newpage, struct page *page,
 606                                 enum migrate_mode mode)
 607 {
 608         int rc;
 609
 610         rc = migrate_huge_page_move_mapping(mapping, newpage, page);
 611         if (rc)
 612                 return rc;
 613         migrate_page_copy(newpage, page);
 614
 615         return 0;
 616 }
 617
 618 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 619 {
 620         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
 621         struct hstate *h = hstate_inode(dentry->d_inode);
 622
 623         buf->f_type = HUGETLBFS_MAGIC;
 624         buf->f_bsize = huge_page_size(h);
 625         if (sbinfo) {
 626                 spin_lock(&sbinfo->stat_lock);
 627                 /* If no limits set, just report 0 for max/free/used
 628                  * blocks, like simple_statfs() */
 629                 if (sbinfo->spool) {
 630                         long free_pages;
 631
 632                         spin_lock(&sbinfo->spool->lock);
 633                         buf->f_blocks = sbinfo->spool->max_hpages;
 634                         free_pages = sbinfo->spool->max_hpages
 635                                 - sbinfo->spool->used_hpages;
 636                         buf->f_bavail = buf->f_bfree = free_pages;
 637                         spin_unlock(&sbinfo->spool->lock);
 638                         buf->f_files = sbinfo->max_inodes;
 639                         buf->f_ffree = sbinfo->free_inodes;
 640                 }
 641                 spin_unlock(&sbinfo->stat_lock);
 642         }
 643         buf->f_namelen = NAME_MAX;
 644         return 0;
 645 }
 646
 647 static void hugetlbfs_put_super(struct super_block *sb)
 648 {
 649         struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
 650
 651         if (sbi) {
 652                 sb->s_fs_info = NULL;
 653
 654                 if (sbi->spool)
 655                         hugepage_put_subpool(sbi->spool);
 656
 657                 kfree(sbi);
 658         }
 659 }
 660
 661 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
 662 {
 663         if (sbinfo->free_inodes >= 0) {
 664                 spin_lock(&sbinfo->stat_lock);
 665                 if (unlikely(!sbinfo->free_inodes)) {
 666                         spin_unlock(&sbinfo->stat_lock);
 667                         return 0;
 668                 }
 669                 sbinfo->free_inodes--;
 670                 spin_unlock(&sbinfo->stat_lock);
 671         }
 672
 673         return 1;
 674 }
 675
 676 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
 677 {
 678         if (sbinfo->free_inodes >= 0) {
 679                 spin_lock(&sbinfo->stat_lock);
 680                 sbinfo->free_inodes++;
 681                 spin_unlock(&sbinfo->stat_lock);
 682         }
 683 }
 684
 685
 686 static struct kmem_cache *hugetlbfs_inode_cachep;
 687
 688 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
 689 {
 690         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
 691         struct hugetlbfs_inode_info *p;
 692
 693         if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
 694                 return NULL;
 695         p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL);
 696         if (unlikely(!p)) {
 697                 hugetlbfs_inc_free_inodes(sbinfo);
 698                 return NULL;
 699         }
 700         return &p->vfs_inode;
 701 }
 702
 703 static void hugetlbfs_i_callback(struct rcu_head *head)
 704 {
 705         struct inode *inode = container_of(head, struct inode, i_rcu);
 706         kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
 707 }
 708
 709 static void hugetlbfs_destroy_inode(struct inode *inode)
 710 {
 711         hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
 712         mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
 713         call_rcu(&inode->i_rcu, hugetlbfs_i_callback);
 714 }
 715
 716 static const struct address_space_operations hugetlbfs_aops = {
 717         .write_begin    = hugetlbfs_write_begin,
 718         .write_end      = hugetlbfs_write_end,
 719         .set_page_dirty = hugetlbfs_set_page_dirty,
 720         .migratepage    = hugetlbfs_migrate_page,
 721 };
 722
 723
 724 static void init_once(void *foo)
 725 {
 726         struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
 727
 728         inode_init_once(&ei->vfs_inode);
 729 }
 730
 731 const struct file_operations hugetlbfs_file_operations = {
 732         .read                   = hugetlbfs_read,
 733         .mmap                   = hugetlbfs_file_mmap,
 734         .fsync                  = noop_fsync,
 735         .get_unmapped_area      = hugetlb_get_unmapped_area,
 736         .llseek         = default_llseek,
 737 };
 738
 739 static const struct inode_operations hugetlbfs_dir_inode_operations = {
 740         .create         = hugetlbfs_create,
 741         .lookup         = simple_lookup,
 742         .link           = simple_link,
 743         .unlink         = simple_unlink,
 744         .symlink        = hugetlbfs_symlink,
 745         .mkdir          = hugetlbfs_mkdir,
 746         .rmdir          = simple_rmdir,
 747         .mknod          = hugetlbfs_mknod,
 748         .rename         = simple_rename,
 749         .setattr        = hugetlbfs_setattr,
 750 };
 751
 752 static const struct inode_operations hugetlbfs_inode_operations = {
 753         .setattr        = hugetlbfs_setattr,
 754 };
 755
 756 static const struct super_operations hugetlbfs_ops = {
 757         .alloc_inode    = hugetlbfs_alloc_inode,
 758         .destroy_inode  = hugetlbfs_destroy_inode,
 759         .evict_inode    = hugetlbfs_evict_inode,
 760         .statfs         = hugetlbfs_statfs,
 761         .put_super      = hugetlbfs_put_super,
 762         .show_options   = generic_show_options,
 763 };
 764
 765 static int
 766 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
 767 {
 768         char *p, *rest;
 769         substring_t args[MAX_OPT_ARGS];
 770         int option;
 771         unsigned long long size = 0;
 772         enum { NO_SIZE, SIZE_STD, SIZE_PERCENT } setsize = NO_SIZE;
 773
 774         if (!options)
 775                 return 0;
 776
 777         while ((p = strsep(&options, ",")) != NULL) {
 778                 int token;
 779                 if (!*p)
 780                         continue;
 781
 782                 token = match_token(p, tokens, args);
 783                 switch (token) {
 784                 case Opt_uid:
 785                         if (match_int(&args[0], &option))
 786                                 goto bad_val;
 787                         pconfig->uid = make_kuid(current_user_ns(), option);
 788                         if (!uid_valid(pconfig->uid))
 789                                 goto bad_val;
 790                         break;
 791
 792                 case Opt_gid:
 793                         if (match_int(&args[0], &option))
 794                                 goto bad_val;
 795                         pconfig->gid = make_kgid(current_user_ns(), option);
 796                         if (!gid_valid(pconfig->gid))
 797                                 goto bad_val;
 798                         break;
 799
 800                 case Opt_mode:
 801                         if (match_octal(&args[0], &option))
 802                                 goto bad_val;
 803                         pconfig->mode = option & 01777U;
 804                         break;
 805
 806                 case Opt_size: {
 807                         /* memparse() will accept a K/M/G without a digit */
 808                         if (!isdigit(*args[0].from))
 809                                 goto bad_val;
 810                         size = memparse(args[0].from, &rest);
 811                         setsize = SIZE_STD;
 812                         if (*rest == '%')
 813                                 setsize = SIZE_PERCENT;
 814                         break;
 815                 }
 816
 817                 case Opt_nr_inodes:
 818                         /* memparse() will accept a K/M/G without a digit */
 819                         if (!isdigit(*args[0].from))
 820                                 goto bad_val;
 821                         pconfig->nr_inodes = memparse(args[0].from, &rest);
 822                         break;
 823
 824                 case Opt_pagesize: {
 825                         unsigned long ps;
 826                         ps = memparse(args[0].from, &rest);
 827                         pconfig->hstate = size_to_hstate(ps);
 828                         if (!pconfig->hstate) {
 829                                 printk(KERN_ERR
 830                                 "hugetlbfs: Unsupported page size %lu MB\n",
 831                                         ps >> 20);
 832                                 return -EINVAL;
 833                         }
 834                         break;
 835                 }
 836
 837                 default:
 838                         printk(KERN_ERR "hugetlbfs: Bad mount option: \"%s\"\n",
 839                                  p);
 840                         return -EINVAL;
 841                         break;
 842                 }
 843         }
 844
 845         /* Do size after hstate is set up */
 846         if (setsize > NO_SIZE) {
 847                 struct hstate *h = pconfig->hstate;
 848                 if (setsize == SIZE_PERCENT) {
 849                         size <<= huge_page_shift(h);
 850                         size *= h->max_huge_pages;
 851                         do_div(size, 100);
 852                 }
 853                 pconfig->nr_blocks = (size >> huge_page_shift(h));
 854         }
 855
 856         return 0;
 857
 858 bad_val:
 859         printk(KERN_ERR "hugetlbfs: Bad value '%s' for mount option '%s'\n",
 860                args[0].from, p);
 861         return -EINVAL;
 862 }
 863
 864 static int
 865 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
 866 {
 867         int ret;
 868         struct hugetlbfs_config config;
 869         struct hugetlbfs_sb_info *sbinfo;
 870
 871         save_mount_options(sb, data);
 872
 873         config.nr_blocks = -1; /* No limit on size by default */
 874         config.nr_inodes = -1; /* No limit on number of inodes by default */
 875         config.uid = current_fsuid();
 876         config.gid = current_fsgid();
 877         config.mode = 0755;
 878         config.hstate = &default_hstate;
 879         ret = hugetlbfs_parse_options(data, &config);
 880         if (ret)
 881                 return ret;
 882
 883         sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
 884         if (!sbinfo)
 885                 return -ENOMEM;
 886         sb->s_fs_info = sbinfo;
 887         sbinfo->hstate = config.hstate;
 888         spin_lock_init(&sbinfo->stat_lock);
 889         sbinfo->max_inodes = config.nr_inodes;
 890         sbinfo->free_inodes = config.nr_inodes;
 891         sbinfo->spool = NULL;
 892         if (config.nr_blocks != -1) {
 893                 sbinfo->spool = hugepage_new_subpool(config.nr_blocks);
 894                 if (!sbinfo->spool)
 895                         goto out_free;
 896         }
 897         sb->s_maxbytes = MAX_LFS_FILESIZE;
 898         sb->s_blocksize = huge_page_size(config.hstate);
 899         sb->s_blocksize_bits = huge_page_shift(config.hstate);
 900         sb->s_magic = HUGETLBFS_MAGIC;
 901         sb->s_op = &hugetlbfs_ops;
 902         sb->s_time_gran = 1;
 903         sb->s_root = d_make_root(hugetlbfs_get_root(sb, &config));
 904         if (!sb->s_root)
 905                 goto out_free;
 906         return 0;
 907 out_free:
 908         if (sbinfo->spool)
 909                 kfree(sbinfo->spool);
 910         kfree(sbinfo);
 911         return -ENOMEM;
 912 }
 913
 914 static struct dentry *hugetlbfs_mount(struct file_system_type *fs_type,
 915         int flags, const char *dev_name, void *data)
 916 {
 917         return mount_nodev(fs_type, flags, data, hugetlbfs_fill_super);
 918 }
 919
 920 static struct file_system_type hugetlbfs_fs_type = {
 921         .name           = "hugetlbfs",
 922         .mount          = hugetlbfs_mount,
 923         .kill_sb        = kill_litter_super,
 924 };
 925
 926 static struct vfsmount *hugetlbfs_vfsmount;
 927
 928 static int can_do_hugetlb_shm(void)
 929 {
 930         kgid_t shm_group;
 931         shm_group = make_kgid(&init_user_ns, sysctl_hugetlb_shm_group);
 932         return capable(CAP_IPC_LOCK) || in_group_p(shm_group);
 933 }
 934
 935 struct file *hugetlb_file_setup(const char *name, unsigned long addr,
 936                                 size_t size, vm_flags_t acctflag,
 937                                 struct user_struct **user, int creat_flags)
 938 {
 939         int error = -ENOMEM;
 940         struct file *file;
 941         struct inode *inode;
 942         struct path path;
 943         struct dentry *root;
 944         struct qstr quick_string;
 945         struct hstate *hstate;
 946         unsigned long num_pages;
 947
 948         *user = NULL;
 949         if (!hugetlbfs_vfsmount)
 950                 return ERR_PTR(-ENOENT);
 951
 952         if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) {
 953                 *user = current_user();
 954                 if (user_shm_lock(size, *user)) {
 955                         task_lock(current);
 956                         printk_once(KERN_WARNING
 957                                 "%s (%d): Using mlock ulimits for SHM_HUGETLB is deprecated\n",
 958                                 current->comm, current->pid);
 959                         task_unlock(current);
 960                 } else {
 961                         *user = NULL;
 962                         return ERR_PTR(-EPERM);
 963                 }
 964         }
 965
 966         root = hugetlbfs_vfsmount->mnt_root;
 967         quick_string.name = name;
 968         quick_string.len = strlen(quick_string.name);
 969         quick_string.hash = 0;
 970         path.dentry = d_alloc(root, &quick_string);
 971         if (!path.dentry)
 972                 goto out_shm_unlock;
 973
 974         path.mnt = mntget(hugetlbfs_vfsmount);
 975         error = -ENOSPC;
 976         inode = hugetlbfs_get_inode(root->d_sb, NULL, S_IFREG | S_IRWXUGO, 0);
 977         if (!inode)
 978                 goto out_dentry;
 979
 980         hstate = hstate_inode(inode);
 981         size += addr & ~huge_page_mask(hstate);
 982         num_pages = ALIGN(size, huge_page_size(hstate)) >>
 983                         huge_page_shift(hstate);
 984         error = -ENOMEM;
 985         if (hugetlb_reserve_pages(inode, 0, num_pages, NULL, acctflag))
 986                 goto out_inode;
 987
 988         d_instantiate(path.dentry, inode);
 989         inode->i_size = size;
 990         clear_nlink(inode);
 991
 992         error = -ENFILE;
 993         file = alloc_file(&path, FMODE_WRITE | FMODE_READ,
 994                         &hugetlbfs_file_operations);
 995         if (!file)
 996                 goto out_dentry; /* inode is already attached */
 997
 998         return file;
 999
1000 out_inode:
1001         iput(inode);
1002 out_dentry:
1003         path_put(&path);
1004 out_shm_unlock:
1005         if (*user) {
1006                 user_shm_unlock(size, *user);
1007                 *user = NULL;
1008         }
1009         return ERR_PTR(error);
1010 }
1011
1012 static int __init init_hugetlbfs_fs(void)
1013 {
1014         int error;
1015         struct vfsmount *vfsmount;
1016
1017         error = bdi_init(&hugetlbfs_backing_dev_info);
1018         if (error)
1019                 return error;
1020
1021         error = -ENOMEM;
1022         hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
1023                                         sizeof(struct hugetlbfs_inode_info),
1024                                         0, 0, init_once);
1025         if (hugetlbfs_inode_cachep == NULL)
1026                 goto out2;
1027
1028         error = register_filesystem(&hugetlbfs_fs_type);
1029         if (error)
1030                 goto out;
1031
1032         vfsmount = kern_mount(&hugetlbfs_fs_type);
1033
1034         if (!IS_ERR(vfsmount)) {
1035                 hugetlbfs_vfsmount = vfsmount;
1036                 return 0;
1037         }
1038
1039         error = PTR_ERR(vfsmount);
1040
1041  out:
1042         kmem_cache_destroy(hugetlbfs_inode_cachep);
1043  out2:
1044         bdi_destroy(&hugetlbfs_backing_dev_info);
1045         return error;
1046 }
1047
1048 static void __exit exit_hugetlbfs_fs(void)
1049 {
1050         /*
1051          * Make sure all delayed rcu free inodes are flushed before we
1052          * destroy cache.
1053          */
1054         rcu_barrier();
1055         kmem_cache_destroy(hugetlbfs_inode_cachep);
1056         kern_unmount(hugetlbfs_vfsmount);
1057         unregister_filesystem(&hugetlbfs_fs_type);
1058         bdi_destroy(&hugetlbfs_backing_dev_info);
1059 }
1060
1061 module_init(init_hugetlbfs_fs)
1062 module_exit(exit_hugetlbfs_fs)
1063
1064 MODULE_LICENSE("GPL");