fs/hugetlbfs/inode.c

   1 /*
   2  * hugetlbpage-backed filesystem.  Based on ramfs.
   3  *
   4  * Nadia Yvette Chambers, 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_inode(file);
 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;
 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         struct hstate *h = hstate_file(file);
 155         struct vm_unmapped_area_info info;
 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         info.flags = 0;
 177         info.length = len;
 178         info.low_limit = TASK_UNMAPPED_BASE;
 179         info.high_limit = TASK_SIZE;
 180         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
 181         info.align_offset = 0;
 182         return vm_unmapped_area(&info);
 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         /* validate length */
 242         if (len == 0)
 243                 goto out;
 244
 245         for (;;) {
 246                 struct page *page;
 247                 unsigned long nr, ret;
 248                 int ra;
 249
 250                 /* nr is the maximum number of bytes to copy from this page */
 251                 nr = huge_page_size(h);
 252                 isize = i_size_read(inode);
 253                 if (!isize)
 254                         goto out;
 255                 end_index = (isize - 1) >> huge_page_shift(h);
 256                 if (index >= end_index) {
 257                         if (index > end_index)
 258                                 goto out;
 259                         nr = ((isize - 1) & ~huge_page_mask(h)) + 1;
 260                         if (nr <= offset)
 261                                 goto out;
 262                 }
 263                 nr = nr - offset;
 264
 265                 /* Find the page */
 266                 page = find_lock_page(mapping, index);
 267                 if (unlikely(page == NULL)) {
 268                         /*
 269                          * We have a HOLE, zero out the user-buffer for the
 270                          * length of the hole or request.
 271                          */
 272                         ret = len < nr ? len : nr;
 273                         if (clear_user(buf, ret))
 274                                 ra = -EFAULT;
 275                         else
 276                                 ra = 0;
 277                 } else {
 278                         unlock_page(page);
 279
 280                         /*
 281                          * We have the page, copy it to user space buffer.
 282                          */
 283                         ra = hugetlbfs_read_actor(page, offset, buf, len, nr);
 284                         ret = ra;
 285                         page_cache_release(page);
 286                 }
 287                 if (ra < 0) {
 288                         if (retval == 0)
 289                                 retval = ra;
 290                         goto out;
 291                 }
 292
 293                 offset += ret;
 294                 retval += ret;
 295                 len -= ret;
 296                 index += offset >> huge_page_shift(h);
 297                 offset &= ~huge_page_mask(h);
 298
 299                 /* short read or no more work */
 300                 if ((ret != nr) || (len == 0))
 301                         break;
 302         }
 303 out:
 304         *ppos = ((loff_t)index << huge_page_shift(h)) + offset;
 305         return retval;
 306 }
 307
 308 static int hugetlbfs_write_begin(struct file *file,
 309                         struct address_space *mapping,
 310                         loff_t pos, unsigned len, unsigned flags,
 311                         struct page **pagep, void **fsdata)
 312 {
 313         return -EINVAL;
 314 }
 315
 316 static int hugetlbfs_write_end(struct file *file, struct address_space *mapping,
 317                         loff_t pos, unsigned len, unsigned copied,
 318                         struct page *page, void *fsdata)
 319 {
 320         BUG();
 321         return -EINVAL;
 322 }
 323
 324 static void truncate_huge_page(struct page *page)
 325 {
 326         cancel_dirty_page(page, /* No IO accounting for huge pages? */0);
 327         ClearPageUptodate(page);
 328         delete_from_page_cache(page);
 329 }
 330
 331 static void truncate_hugepages(struct inode *inode, loff_t lstart)
 332 {
 333         struct hstate *h = hstate_inode(inode);
 334         struct address_space *mapping = &inode->i_data;
 335         const pgoff_t start = lstart >> huge_page_shift(h);
 336         struct pagevec pvec;
 337         pgoff_t next;
 338         int i, freed = 0;
 339
 340         pagevec_init(&pvec, 0);
 341         next = start;
 342         while (1) {
 343                 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
 344                         if (next == start)
 345                                 break;
 346                         next = start;
 347                         continue;
 348                 }
 349
 350                 for (i = 0; i < pagevec_count(&pvec); ++i) {
 351                         struct page *page = pvec.pages[i];
 352
 353                         lock_page(page);
 354                         if (page->index > next)
 355                                 next = page->index;
 356                         ++next;
 357                         truncate_huge_page(page);
 358                         unlock_page(page);
 359                         freed++;
 360                 }
 361                 huge_pagevec_release(&pvec);
 362         }
 363         BUG_ON(!lstart && mapping->nrpages);
 364         hugetlb_unreserve_pages(inode, start, freed);
 365 }
 366
 367 static void hugetlbfs_evict_inode(struct inode *inode)
 368 {
 369         struct resv_map *resv_map;
 370
 371         truncate_hugepages(inode, 0);
 372         resv_map = (struct resv_map *)inode->i_mapping->private_data;
 373         /* root inode doesn't have the resv_map, so we should check it */
 374         if (resv_map)
 375                 resv_map_release(&resv_map->refs);
 376         clear_inode(inode);
 377 }
 378
 379 static inline void
 380 hugetlb_vmtruncate_list(struct rb_root *root, pgoff_t pgoff)
 381 {
 382         struct vm_area_struct *vma;
 383
 384         vma_interval_tree_foreach(vma, root, pgoff, ULONG_MAX) {
 385                 unsigned long v_offset;
 386
 387                 /*
 388                  * Can the expression below overflow on 32-bit arches?
 389                  * No, because the interval tree returns us only those vmas
 390                  * which overlap the truncated area starting at pgoff,
 391                  * and no vma on a 32-bit arch can span beyond the 4GB.
 392                  */
 393                 if (vma->vm_pgoff < pgoff)
 394                         v_offset = (pgoff - vma->vm_pgoff) << PAGE_SHIFT;
 395                 else
 396                         v_offset = 0;
 397
 398                 unmap_hugepage_range(vma, vma->vm_start + v_offset,
 399                                      vma->vm_end, NULL);
 400         }
 401 }
 402
 403 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
 404 {
 405         pgoff_t pgoff;
 406         struct address_space *mapping = inode->i_mapping;
 407         struct hstate *h = hstate_inode(inode);
 408
 409         BUG_ON(offset & ~huge_page_mask(h));
 410         pgoff = offset >> PAGE_SHIFT;
 411
 412         i_size_write(inode, offset);
 413         mutex_lock(&mapping->i_mmap_mutex);
 414         if (!RB_EMPTY_ROOT(&mapping->i_mmap))
 415                 hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff);
 416         mutex_unlock(&mapping->i_mmap_mutex);
 417         truncate_hugepages(inode, offset);
 418         return 0;
 419 }
 420
 421 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
 422 {
 423         struct inode *inode = dentry->d_inode;
 424         struct hstate *h = hstate_inode(inode);
 425         int error;
 426         unsigned int ia_valid = attr->ia_valid;
 427
 428         BUG_ON(!inode);
 429
 430         error = inode_change_ok(inode, attr);
 431         if (error)
 432                 return error;
 433
 434         if (ia_valid & ATTR_SIZE) {
 435                 error = -EINVAL;
 436                 if (attr->ia_size & ~huge_page_mask(h))
 437                         return -EINVAL;
 438                 error = hugetlb_vmtruncate(inode, attr->ia_size);
 439                 if (error)
 440                         return error;
 441         }
 442
 443         setattr_copy(inode, attr);
 444         mark_inode_dirty(inode);
 445         return 0;
 446 }
 447
 448 static struct inode *hugetlbfs_get_root(struct super_block *sb,
 449                                         struct hugetlbfs_config *config)
 450 {
 451         struct inode *inode;
 452
 453         inode = new_inode(sb);
 454         if (inode) {
 455                 struct hugetlbfs_inode_info *info;
 456                 inode->i_ino = get_next_ino();
 457                 inode->i_mode = S_IFDIR | config->mode;
 458                 inode->i_uid = config->uid;
 459                 inode->i_gid = config->gid;
 460                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 461                 info = HUGETLBFS_I(inode);
 462                 mpol_shared_policy_init(&info->policy, NULL);
 463                 inode->i_op = &hugetlbfs_dir_inode_operations;
 464                 inode->i_fop = &simple_dir_operations;
 465                 /* directory inodes start off with i_nlink == 2 (for "." entry) */
 466                 inc_nlink(inode);
 467                 lockdep_annotate_inode_mutex_key(inode);
 468         }
 469         return inode;
 470 }
 471
 472 /*
 473  * Hugetlbfs is not reclaimable; therefore its i_mmap_mutex will never
 474  * be taken from reclaim -- unlike regular filesystems. This needs an
 475  * annotation because huge_pmd_share() does an allocation under
 476  * i_mmap_mutex.
 477  */
 478 struct lock_class_key hugetlbfs_i_mmap_mutex_key;
 479
 480 static struct inode *hugetlbfs_get_inode(struct super_block *sb,
 481                                         struct inode *dir,
 482                                         umode_t mode, dev_t dev)
 483 {
 484         struct inode *inode;
 485         struct resv_map *resv_map;
 486
 487         resv_map = resv_map_alloc();
 488         if (!resv_map)
 489                 return NULL;
 490
 491         inode = new_inode(sb);
 492         if (inode) {
 493                 struct hugetlbfs_inode_info *info;
 494                 inode->i_ino = get_next_ino();
 495                 inode_init_owner(inode, dir, mode);
 496                 lockdep_set_class(&inode->i_mapping->i_mmap_mutex,
 497                                 &hugetlbfs_i_mmap_mutex_key);
 498                 inode->i_mapping->a_ops = &hugetlbfs_aops;
 499                 inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info;
 500                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 501                 inode->i_mapping->private_data = resv_map;
 502                 info = HUGETLBFS_I(inode);
 503                 /*
 504                  * The policy is initialized here even if we are creating a
 505                  * private inode because initialization simply creates an
 506                  * an empty rb tree and calls spin_lock_init(), later when we
 507                  * call mpol_free_shared_policy() it will just return because
 508                  * the rb tree will still be empty.
 509                  */
 510                 mpol_shared_policy_init(&info->policy, NULL);
 511                 switch (mode & S_IFMT) {
 512                 default:
 513                         init_special_inode(inode, mode, dev);
 514                         break;
 515                 case S_IFREG:
 516                         inode->i_op = &hugetlbfs_inode_operations;
 517                         inode->i_fop = &hugetlbfs_file_operations;
 518                         break;
 519                 case S_IFDIR:
 520                         inode->i_op = &hugetlbfs_dir_inode_operations;
 521                         inode->i_fop = &simple_dir_operations;
 522
 523                         /* directory inodes start off with i_nlink == 2 (for "." entry) */
 524                         inc_nlink(inode);
 525                         break;
 526                 case S_IFLNK:
 527                         inode->i_op = &page_symlink_inode_operations;
 528                         break;
 529                 }
 530                 lockdep_annotate_inode_mutex_key(inode);
 531         } else
 532                 kref_put(&resv_map->refs, resv_map_release);
 533
 534         return inode;
 535 }
 536
 537 /*
 538  * File creation. Allocate an inode, and we're done..
 539  */
 540 static int hugetlbfs_mknod(struct inode *dir,
 541                         struct dentry *dentry, umode_t mode, dev_t dev)
 542 {
 543         struct inode *inode;
 544         int error = -ENOSPC;
 545
 546         inode = hugetlbfs_get_inode(dir->i_sb, dir, mode, dev);
 547         if (inode) {
 548                 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 549                 d_instantiate(dentry, inode);
 550                 dget(dentry);   /* Extra count - pin the dentry in core */
 551                 error = 0;
 552         }
 553         return error;
 554 }
 555
 556 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 557 {
 558         int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
 559         if (!retval)
 560                 inc_nlink(dir);
 561         return retval;
 562 }
 563
 564 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl)
 565 {
 566         return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
 567 }
 568
 569 static int hugetlbfs_symlink(struct inode *dir,
 570                         struct dentry *dentry, const char *symname)
 571 {
 572         struct inode *inode;
 573         int error = -ENOSPC;
 574
 575         inode = hugetlbfs_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0);
 576         if (inode) {
 577                 int l = strlen(symname)+1;
 578                 error = page_symlink(inode, symname, l);
 579                 if (!error) {
 580                         d_instantiate(dentry, inode);
 581                         dget(dentry);
 582                 } else
 583                         iput(inode);
 584         }
 585         dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 586
 587         return error;
 588 }
 589
 590 /*
 591  * mark the head page dirty
 592  */
 593 static int hugetlbfs_set_page_dirty(struct page *page)
 594 {
 595         struct page *head = compound_head(page);
 596
 597         SetPageDirty(head);
 598         return 0;
 599 }
 600
 601 static int hugetlbfs_migrate_page(struct address_space *mapping,
 602                                 struct page *newpage, struct page *page,
 603                                 enum migrate_mode mode)
 604 {
 605         int rc;
 606
 607         rc = migrate_huge_page_move_mapping(mapping, newpage, page);
 608         if (rc != MIGRATEPAGE_SUCCESS)
 609                 return rc;
 610         migrate_page_copy(newpage, page);
 611
 612         return MIGRATEPAGE_SUCCESS;
 613 }
 614
 615 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 616 {
 617         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
 618         struct hstate *h = hstate_inode(dentry->d_inode);
 619
 620         buf->f_type = HUGETLBFS_MAGIC;
 621         buf->f_bsize = huge_page_size(h);
 622         if (sbinfo) {
 623                 spin_lock(&sbinfo->stat_lock);
 624                 /* If no limits set, just report 0 for max/free/used
 625                  * blocks, like simple_statfs() */
 626                 if (sbinfo->spool) {
 627                         long free_pages;
 628
 629                         spin_lock(&sbinfo->spool->lock);
 630                         buf->f_blocks = sbinfo->spool->max_hpages;
 631                         free_pages = sbinfo->spool->max_hpages
 632                                 - sbinfo->spool->used_hpages;
 633                         buf->f_bavail = buf->f_bfree = free_pages;
 634                         spin_unlock(&sbinfo->spool->lock);
 635                         buf->f_files = sbinfo->max_inodes;
 636                         buf->f_ffree = sbinfo->free_inodes;
 637                 }
 638                 spin_unlock(&sbinfo->stat_lock);
 639         }
 640         buf->f_namelen = NAME_MAX;
 641         return 0;
 642 }
 643
 644 static void hugetlbfs_put_super(struct super_block *sb)
 645 {
 646         struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
 647
 648         if (sbi) {
 649                 sb->s_fs_info = NULL;
 650
 651                 if (sbi->spool)
 652                         hugepage_put_subpool(sbi->spool);
 653
 654                 kfree(sbi);
 655         }
 656 }
 657
 658 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
 659 {
 660         if (sbinfo->free_inodes >= 0) {
 661                 spin_lock(&sbinfo->stat_lock);
 662                 if (unlikely(!sbinfo->free_inodes)) {
 663                         spin_unlock(&sbinfo->stat_lock);
 664                         return 0;
 665                 }
 666                 sbinfo->free_inodes--;
 667                 spin_unlock(&sbinfo->stat_lock);
 668         }
 669
 670         return 1;
 671 }
 672
 673 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
 674 {
 675         if (sbinfo->free_inodes >= 0) {
 676                 spin_lock(&sbinfo->stat_lock);
 677                 sbinfo->free_inodes++;
 678                 spin_unlock(&sbinfo->stat_lock);
 679         }
 680 }
 681
 682
 683 static struct kmem_cache *hugetlbfs_inode_cachep;
 684
 685 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
 686 {
 687         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
 688         struct hugetlbfs_inode_info *p;
 689
 690         if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
 691                 return NULL;
 692         p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL);
 693         if (unlikely(!p)) {
 694                 hugetlbfs_inc_free_inodes(sbinfo);
 695                 return NULL;
 696         }
 697         return &p->vfs_inode;
 698 }
 699
 700 static void hugetlbfs_i_callback(struct rcu_head *head)
 701 {
 702         struct inode *inode = container_of(head, struct inode, i_rcu);
 703         kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
 704 }
 705
 706 static void hugetlbfs_destroy_inode(struct inode *inode)
 707 {
 708         hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
 709         mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
 710         call_rcu(&inode->i_rcu, hugetlbfs_i_callback);
 711 }
 712
 713 static const struct address_space_operations hugetlbfs_aops = {
 714         .write_begin    = hugetlbfs_write_begin,
 715         .write_end      = hugetlbfs_write_end,
 716         .set_page_dirty = hugetlbfs_set_page_dirty,
 717         .migratepage    = hugetlbfs_migrate_page,
 718 };
 719
 720
 721 static void init_once(void *foo)
 722 {
 723         struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
 724
 725         inode_init_once(&ei->vfs_inode);
 726 }
 727
 728 const struct file_operations hugetlbfs_file_operations = {
 729         .read                   = hugetlbfs_read,
 730         .mmap                   = hugetlbfs_file_mmap,
 731         .fsync                  = noop_fsync,
 732         .get_unmapped_area      = hugetlb_get_unmapped_area,
 733         .llseek         = default_llseek,
 734 };
 735
 736 static const struct inode_operations hugetlbfs_dir_inode_operations = {
 737         .create         = hugetlbfs_create,
 738         .lookup         = simple_lookup,
 739         .link           = simple_link,
 740         .unlink         = simple_unlink,
 741         .symlink        = hugetlbfs_symlink,
 742         .mkdir          = hugetlbfs_mkdir,
 743         .rmdir          = simple_rmdir,
 744         .mknod          = hugetlbfs_mknod,
 745         .rename         = simple_rename,
 746         .setattr        = hugetlbfs_setattr,
 747 };
 748
 749 static const struct inode_operations hugetlbfs_inode_operations = {
 750         .setattr        = hugetlbfs_setattr,
 751 };
 752
 753 static const struct super_operations hugetlbfs_ops = {
 754         .alloc_inode    = hugetlbfs_alloc_inode,
 755         .destroy_inode  = hugetlbfs_destroy_inode,
 756         .evict_inode    = hugetlbfs_evict_inode,
 757         .statfs         = hugetlbfs_statfs,
 758         .put_super      = hugetlbfs_put_super,
 759         .show_options   = generic_show_options,
 760 };
 761
 762 static int
 763 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
 764 {
 765         char *p, *rest;
 766         substring_t args[MAX_OPT_ARGS];
 767         int option;
 768         unsigned long long size = 0;
 769         enum { NO_SIZE, SIZE_STD, SIZE_PERCENT } setsize = NO_SIZE;
 770
 771         if (!options)
 772                 return 0;
 773
 774         while ((p = strsep(&options, ",")) != NULL) {
 775                 int token;
 776                 if (!*p)
 777                         continue;
 778
 779                 token = match_token(p, tokens, args);
 780                 switch (token) {
 781                 case Opt_uid:
 782                         if (match_int(&args[0], &option))
 783                                 goto bad_val;
 784                         pconfig->uid = make_kuid(current_user_ns(), option);
 785                         if (!uid_valid(pconfig->uid))
 786                                 goto bad_val;
 787                         break;
 788
 789                 case Opt_gid:
 790                         if (match_int(&args[0], &option))
 791                                 goto bad_val;
 792                         pconfig->gid = make_kgid(current_user_ns(), option);
 793                         if (!gid_valid(pconfig->gid))
 794                                 goto bad_val;
 795                         break;
 796
 797                 case Opt_mode:
 798                         if (match_octal(&args[0], &option))
 799                                 goto bad_val;
 800                         pconfig->mode = option & 01777U;
 801                         break;
 802
 803                 case Opt_size: {
 804                         /* memparse() will accept a K/M/G without a digit */
 805                         if (!isdigit(*args[0].from))
 806                                 goto bad_val;
 807                         size = memparse(args[0].from, &rest);
 808                         setsize = SIZE_STD;
 809                         if (*rest == '%')
 810                                 setsize = SIZE_PERCENT;
 811                         break;
 812                 }
 813
 814                 case Opt_nr_inodes:
 815                         /* memparse() will accept a K/M/G without a digit */
 816                         if (!isdigit(*args[0].from))
 817                                 goto bad_val;
 818                         pconfig->nr_inodes = memparse(args[0].from, &rest);
 819                         break;
 820
 821                 case Opt_pagesize: {
 822                         unsigned long ps;
 823                         ps = memparse(args[0].from, &rest);
 824                         pconfig->hstate = size_to_hstate(ps);
 825                         if (!pconfig->hstate) {
 826                                 printk(KERN_ERR
 827                                 "hugetlbfs: Unsupported page size %lu MB\n",
 828                                         ps >> 20);
 829                                 return -EINVAL;
 830                         }
 831                         break;
 832                 }
 833
 834                 default:
 835                         printk(KERN_ERR "hugetlbfs: Bad mount option: \"%s\"\n",
 836                                  p);
 837                         return -EINVAL;
 838                         break;
 839                 }
 840         }
 841
 842         /* Do size after hstate is set up */
 843         if (setsize > NO_SIZE) {
 844                 struct hstate *h = pconfig->hstate;
 845                 if (setsize == SIZE_PERCENT) {
 846                         size <<= huge_page_shift(h);
 847                         size *= h->max_huge_pages;
 848                         do_div(size, 100);
 849                 }
 850                 pconfig->nr_blocks = (size >> huge_page_shift(h));
 851         }
 852
 853         return 0;
 854
 855 bad_val:
 856         printk(KERN_ERR "hugetlbfs: Bad value '%s' for mount option '%s'\n",
 857                args[0].from, p);
 858         return -EINVAL;
 859 }
 860
 861 static int
 862 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
 863 {
 864         int ret;
 865         struct hugetlbfs_config config;
 866         struct hugetlbfs_sb_info *sbinfo;
 867
 868         save_mount_options(sb, data);
 869
 870         config.nr_blocks = -1; /* No limit on size by default */
 871         config.nr_inodes = -1; /* No limit on number of inodes by default */
 872         config.uid = current_fsuid();
 873         config.gid = current_fsgid();
 874         config.mode = 0755;
 875         config.hstate = &default_hstate;
 876         ret = hugetlbfs_parse_options(data, &config);
 877         if (ret)
 878                 return ret;
 879
 880         sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
 881         if (!sbinfo)
 882                 return -ENOMEM;
 883         sb->s_fs_info = sbinfo;
 884         sbinfo->hstate = config.hstate;
 885         spin_lock_init(&sbinfo->stat_lock);
 886         sbinfo->max_inodes = config.nr_inodes;
 887         sbinfo->free_inodes = config.nr_inodes;
 888         sbinfo->spool = NULL;
 889         if (config.nr_blocks != -1) {
 890                 sbinfo->spool = hugepage_new_subpool(config.nr_blocks);
 891                 if (!sbinfo->spool)
 892                         goto out_free;
 893         }
 894         sb->s_maxbytes = MAX_LFS_FILESIZE;
 895         sb->s_blocksize = huge_page_size(config.hstate);
 896         sb->s_blocksize_bits = huge_page_shift(config.hstate);
 897         sb->s_magic = HUGETLBFS_MAGIC;
 898         sb->s_op = &hugetlbfs_ops;
 899         sb->s_time_gran = 1;
 900         sb->s_root = d_make_root(hugetlbfs_get_root(sb, &config));
 901         if (!sb->s_root)
 902                 goto out_free;
 903         return 0;
 904 out_free:
 905         if (sbinfo->spool)
 906                 kfree(sbinfo->spool);
 907         kfree(sbinfo);
 908         return -ENOMEM;
 909 }
 910
 911 static struct dentry *hugetlbfs_mount(struct file_system_type *fs_type,
 912         int flags, const char *dev_name, void *data)
 913 {
 914         return mount_nodev(fs_type, flags, data, hugetlbfs_fill_super);
 915 }
 916
 917 static struct file_system_type hugetlbfs_fs_type = {
 918         .name           = "hugetlbfs",
 919         .mount          = hugetlbfs_mount,
 920         .kill_sb        = kill_litter_super,
 921 };
 922 MODULE_ALIAS_FS("hugetlbfs");
 923
 924 static struct vfsmount *hugetlbfs_vfsmount[HUGE_MAX_HSTATE];
 925
 926 static int can_do_hugetlb_shm(void)
 927 {
 928         kgid_t shm_group;
 929         shm_group = make_kgid(&init_user_ns, sysctl_hugetlb_shm_group);
 930         return capable(CAP_IPC_LOCK) || in_group_p(shm_group);
 931 }
 932
 933 static int get_hstate_idx(int page_size_log)
 934 {
 935         struct hstate *h = hstate_sizelog(page_size_log);
 936
 937         if (!h)
 938                 return -1;
 939         return h - hstates;
 940 }
 941
 942 static struct dentry_operations anon_ops = {
 943         .d_dname = simple_dname
 944 };
 945
 946 /*
 947  * Note that size should be aligned to proper hugepage size in caller side,
 948  * otherwise hugetlb_reserve_pages reserves one less hugepages than intended.
 949  */
 950 struct file *hugetlb_file_setup(const char *name, size_t size,
 951                                 vm_flags_t acctflag, struct user_struct **user,
 952                                 int creat_flags, int page_size_log)
 953 {
 954         struct file *file = ERR_PTR(-ENOMEM);
 955         struct inode *inode;
 956         struct path path;
 957         struct super_block *sb;
 958         struct qstr quick_string;
 959         int hstate_idx;
 960
 961         hstate_idx = get_hstate_idx(page_size_log);
 962         if (hstate_idx < 0)
 963                 return ERR_PTR(-ENODEV);
 964
 965         *user = NULL;
 966         if (!hugetlbfs_vfsmount[hstate_idx])
 967                 return ERR_PTR(-ENOENT);
 968
 969         if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) {
 970                 *user = current_user();
 971                 if (user_shm_lock(size, *user)) {
 972                         task_lock(current);
 973                         printk_once(KERN_WARNING
 974                                 "%s (%d): Using mlock ulimits for SHM_HUGETLB is deprecated\n",
 975                                 current->comm, current->pid);
 976                         task_unlock(current);
 977                 } else {
 978                         *user = NULL;
 979                         return ERR_PTR(-EPERM);
 980                 }
 981         }
 982
 983         sb = hugetlbfs_vfsmount[hstate_idx]->mnt_sb;
 984         quick_string.name = name;
 985         quick_string.len = strlen(quick_string.name);
 986         quick_string.hash = 0;
 987         path.dentry = d_alloc_pseudo(sb, &quick_string);
 988         if (!path.dentry)
 989                 goto out_shm_unlock;
 990
 991         d_set_d_op(path.dentry, &anon_ops);
 992         path.mnt = mntget(hugetlbfs_vfsmount[hstate_idx]);
 993         file = ERR_PTR(-ENOSPC);
 994         inode = hugetlbfs_get_inode(sb, NULL, S_IFREG | S_IRWXUGO, 0);
 995         if (!inode)
 996                 goto out_dentry;
 997
 998         file = ERR_PTR(-ENOMEM);
 999         if (hugetlb_reserve_pages(inode, 0,
1000                         size >> huge_page_shift(hstate_inode(inode)), NULL,
1001                         acctflag))
1002                 goto out_inode;
1003
1004         d_instantiate(path.dentry, inode);
1005         inode->i_size = size;
1006         clear_nlink(inode);
1007
1008         file = alloc_file(&path, FMODE_WRITE | FMODE_READ,
1009                         &hugetlbfs_file_operations);
1010         if (IS_ERR(file))
1011                 goto out_dentry; /* inode is already attached */
1012
1013         return file;
1014
1015 out_inode:
1016         iput(inode);
1017 out_dentry:
1018         path_put(&path);
1019 out_shm_unlock:
1020         if (*user) {
1021                 user_shm_unlock(size, *user);
1022                 *user = NULL;
1023         }
1024         return file;
1025 }
1026
1027 static int __init init_hugetlbfs_fs(void)
1028 {
1029         struct hstate *h;
1030         int error;
1031         int i;
1032
1033         if (!hugepages_supported()) {
1034                 pr_info("hugetlbfs: disabling because there are no supported hugepage sizes\n");
1035                 return -ENOTSUPP;
1036         }
1037
1038         error = bdi_init(&hugetlbfs_backing_dev_info);
1039         if (error)
1040                 return error;
1041
1042         error = -ENOMEM;
1043         hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
1044                                         sizeof(struct hugetlbfs_inode_info),
1045                                         0, 0, init_once);
1046         if (hugetlbfs_inode_cachep == NULL)
1047                 goto out2;
1048
1049         error = register_filesystem(&hugetlbfs_fs_type);
1050         if (error)
1051                 goto out;
1052
1053         i = 0;
1054         for_each_hstate(h) {
1055                 char buf[50];
1056                 unsigned ps_kb = 1U << (h->order + PAGE_SHIFT - 10);
1057
1058                 snprintf(buf, sizeof(buf), "pagesize=%uK", ps_kb);
1059                 hugetlbfs_vfsmount[i] = kern_mount_data(&hugetlbfs_fs_type,
1060                                                         buf);
1061
1062                 if (IS_ERR(hugetlbfs_vfsmount[i])) {
1063                         pr_err("hugetlb: Cannot mount internal hugetlbfs for "
1064                                 "page size %uK", ps_kb);
1065                         error = PTR_ERR(hugetlbfs_vfsmount[i]);
1066                         hugetlbfs_vfsmount[i] = NULL;
1067                 }
1068                 i++;
1069         }
1070         /* Non default hstates are optional */
1071         if (!IS_ERR_OR_NULL(hugetlbfs_vfsmount[default_hstate_idx]))
1072                 return 0;
1073
1074  out:
1075         kmem_cache_destroy(hugetlbfs_inode_cachep);
1076  out2:
1077         bdi_destroy(&hugetlbfs_backing_dev_info);
1078         return error;
1079 }
1080
1081 static void __exit exit_hugetlbfs_fs(void)
1082 {
1083         struct hstate *h;
1084         int i;
1085
1086
1087         /*
1088          * Make sure all delayed rcu free inodes are flushed before we
1089          * destroy cache.
1090          */
1091         rcu_barrier();
1092         kmem_cache_destroy(hugetlbfs_inode_cachep);
1093         i = 0;
1094         for_each_hstate(h)
1095                 kern_unmount(hugetlbfs_vfsmount[i++]);
1096         unregister_filesystem(&hugetlbfs_fs_type);
1097         bdi_destroy(&hugetlbfs_backing_dev_info);
1098 }
1099
1100 module_init(init_hugetlbfs_fs)
1101 module_exit(exit_hugetlbfs_fs)
1102
1103 MODULE_LICENSE("GPL");