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