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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  10
  11 #include <linux/module.h>
  12 #include <linux/thread_info.h>
  13 #include <asm/current.h>
  14 #include <linux/sched.h>                /* remove ASAP */
  15 #include <linux/fs.h>
  16 #include <linux/mount.h>
  17 #include <linux/file.h>
  18 #include <linux/kernel.h>
  19 #include <linux/writeback.h>
  20 #include <linux/pagemap.h>
  21 #include <linux/highmem.h>
  22 #include <linux/init.h>
  23 #include <linux/string.h>
  24 #include <linux/capability.h>
  25 #include <linux/ctype.h>
  26 #include <linux/backing-dev.h>
  27 #include <linux/hugetlb.h>
  28 #include <linux/pagevec.h>
  29 #include <linux/parser.h>
  30 #include <linux/mman.h>
  31 #include <linux/slab.h>
  32 #include <linux/dnotify.h>
  33 #include <linux/statfs.h>
  34 #include <linux/security.h>
  35 #include <linux/magic.h>
  36 #include <linux/migrate.h>
  37
  38 #include <asm/uaccess.h>
  39
  40 static const struct super_operations hugetlbfs_ops;
  41 static const struct address_space_operations hugetlbfs_aops;
  42 const struct file_operations hugetlbfs_file_operations;
  43 static const struct inode_operations hugetlbfs_dir_inode_operations;
  44 static const struct inode_operations hugetlbfs_inode_operations;
  45
  46 struct hugetlbfs_config {
  47         kuid_t   uid;
  48         kgid_t   gid;
  49         umode_t mode;
  50         long    nr_blocks;
  51         long    nr_inodes;
  52         struct hstate *hstate;
  53 };
  54
  55 struct hugetlbfs_inode_info {
  56         struct shared_policy policy;
  57         struct inode vfs_inode;
  58 };
  59
  60 static inline struct hugetlbfs_inode_info *HUGETLBFS_I(struct inode *inode)
  61 {
  62         return container_of(inode, struct hugetlbfs_inode_info, vfs_inode);
  63 }
  64
  65 static struct backing_dev_info hugetlbfs_backing_dev_info = {
  66         .name           = "hugetlbfs",
  67         .ra_pages       = 0,    /* No readahead */
  68         .capabilities   = BDI_CAP_NO_ACCT_AND_WRITEBACK,
  69 };
  70
  71 int sysctl_hugetlb_shm_group;
  72
  73 enum {
  74         Opt_size, Opt_nr_inodes,
  75         Opt_mode, Opt_uid, Opt_gid,
  76         Opt_pagesize,
  77         Opt_err,
  78 };
  79
  80 static const match_table_t tokens = {
  81         {Opt_size,      "size=%s"},
  82         {Opt_nr_inodes, "nr_inodes=%s"},
  83         {Opt_mode,      "mode=%o"},
  84         {Opt_uid,       "uid=%u"},
  85         {Opt_gid,       "gid=%u"},
  86         {Opt_pagesize,  "pagesize=%s"},
  87         {Opt_err,       NULL},
  88 };
  89
  90 static void huge_pagevec_release(struct pagevec *pvec)
  91 {
  92         int i;
  93
  94         for (i = 0; i < pagevec_count(pvec); ++i)
  95                 put_page(pvec->pages[i]);
  96
  97         pagevec_reinit(pvec);
  98 }
  99
 100 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
 101 {
 102         struct inode *inode = file_inode(file);
 103         loff_t len, vma_len;
 104         int ret;
 105         struct hstate *h = hstate_file(file);
 106
 107         /*
 108          * vma address alignment (but not the pgoff alignment) has
 109          * already been checked by prepare_hugepage_range.  If you add
 110          * any error returns here, do so after setting VM_HUGETLB, so
 111          * is_vm_hugetlb_page tests below unmap_region go the right
 112          * way when do_mmap_pgoff unwinds (may be important on powerpc
 113          * and ia64).
 114          */
 115         vma->vm_flags |= VM_HUGETLB | VM_DONTEXPAND;
 116         vma->vm_ops = &hugetlb_vm_ops;
 117
 118         if (vma->vm_pgoff & (~huge_page_mask(h) >> PAGE_SHIFT))
 119                 return -EINVAL;
 120
 121         vma_len = (loff_t)(vma->vm_end - vma->vm_start);
 122
 123         mutex_lock(&inode->i_mutex);
 124         file_accessed(file);
 125
 126         ret = -ENOMEM;
 127         len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
 128
 129         if (hugetlb_reserve_pages(inode,
 130                                 vma->vm_pgoff >> huge_page_order(h),
 131                                 len >> huge_page_shift(h), vma,
 132                                 vma->vm_flags))
 133                 goto out;
 134
 135         ret = 0;
 136         hugetlb_prefault_arch_hook(vma->vm_mm);
 137         if (vma->vm_flags & VM_WRITE && inode->i_size < len)
 138                 inode->i_size = len;
 139 out:
 140         mutex_unlock(&inode->i_mutex);
 141
 142         return ret;
 143 }
 144
 145 /*
 146  * Called under down_write(mmap_sem).
 147  */
 148
 149 #ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
 150 static unsigned long
 151 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 152                 unsigned long len, unsigned long pgoff, unsigned long flags)
 153 {
 154         struct mm_struct *mm = current->mm;
 155         struct vm_area_struct *vma;
 156         struct hstate *h = hstate_file(file);
 157         struct vm_unmapped_area_info info;
 158
 159         if (len & ~huge_page_mask(h))
 160                 return -EINVAL;
 161         if (len > TASK_SIZE)
 162                 return -ENOMEM;
 163
 164         if (flags & MAP_FIXED) {
 165                 if (prepare_hugepage_range(file, addr, len))
 166                         return -EINVAL;
 167                 return addr;
 168         }
 169
 170         if (addr) {
 171                 addr = ALIGN(addr, huge_page_size(h));
 172                 vma = find_vma(mm, addr);
 173                 if (TASK_SIZE - len >= addr &&
 174                     (!vma || addr + len <= vma->vm_start))
 175                         return addr;
 176         }
 177
 178         info.flags = 0;
 179         info.length = len;
 180         info.low_limit = TASK_UNMAPPED_BASE;
 181         info.high_limit = TASK_SIZE;
 182         info.align_mask = PAGE_MASK & ~huge_page_mask(h);
 183         info.align_offset = 0;
 184         return vm_unmapped_area(&info);
 185 }
 186 #endif
 187
 188 static int
 189 hugetlbfs_read_actor(struct page *page, unsigned long offset,
 190                         char __user *buf, unsigned long count,
 191                         unsigned long size)
 192 {
 193         char *kaddr;
 194         unsigned long left, copied = 0;
 195         int i, chunksize;
 196
 197         if (size > count)
 198                 size = count;
 199
 200         /* Find which 4k chunk and offset with in that chunk */
 201         i = offset >> PAGE_CACHE_SHIFT;
 202         offset = offset & ~PAGE_CACHE_MASK;
 203
 204         while (size) {
 205                 chunksize = PAGE_CACHE_SIZE;
 206                 if (offset)
 207                         chunksize -= offset;
 208                 if (chunksize > size)
 209                         chunksize = size;
 210                 kaddr = kmap(&page[i]);
 211                 left = __copy_to_user(buf, kaddr + offset, chunksize);
 212                 kunmap(&page[i]);
 213                 if (left) {
 214                         copied += (chunksize - left);
 215                         break;
 216                 }
 217                 offset = 0;
 218                 size -= chunksize;
 219                 buf += chunksize;
 220                 copied += chunksize;
 221                 i++;
 222         }
 223         return copied ? copied : -EFAULT;
 224 }
 225
 226 /*
 227  * Support for read() - Find the page attached to f_mapping and copy out the
 228  * data. Its *very* similar to do_generic_mapping_read(), we can't use that
 229  * since it has PAGE_CACHE_SIZE assumptions.
 230  */
 231 static ssize_t hugetlbfs_read(struct file *filp, char __user *buf,
 232                               size_t len, loff_t *ppos)
 233 {
 234         struct hstate *h = hstate_file(filp);
 235         struct address_space *mapping = filp->f_mapping;
 236         struct inode *inode = mapping->host;
 237         unsigned long index = *ppos >> huge_page_shift(h);
 238         unsigned long offset = *ppos & ~huge_page_mask(h);
 239         unsigned long end_index;
 240         loff_t isize;
 241         ssize_t retval = 0;
 242
 243         /* validate length */
 244         if (len == 0)
 245                 goto out;
 246
 247         for (;;) {
 248                 struct page *page;
 249                 unsigned long nr, ret;
 250                 int ra;
 251
 252                 /* nr is the maximum number of bytes to copy from this page */
 253                 nr = huge_page_size(h);
 254                 isize = i_size_read(inode);
 255                 if (!isize)
 256                         goto out;
 257                 end_index = (isize - 1) >> huge_page_shift(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                 nr = nr - offset;
 266
 267                 /* Find the page */
 268                 page = find_lock_page(mapping, index);
 269                 if (unlikely(page == NULL)) {
 270                         /*
 271                          * We have a HOLE, zero out the user-buffer for the
 272                          * length of the hole or request.
 273                          */
 274                         ret = len < nr ? len : nr;
 275                         if (clear_user(buf, ret))
 276                                 ra = -EFAULT;
 277                         else
 278                                 ra = 0;
 279                 } else {
 280                         unlock_page(page);
 281
 282                         /*
 283                          * We have the page, copy it to user space buffer.
 284                          */
 285                         ra = hugetlbfs_read_actor(page, offset, buf, len, nr);
 286                         ret = ra;
 287                         page_cache_release(page);
 288                 }
 289                 if (ra < 0) {
 290                         if (retval == 0)
 291                                 retval = ra;
 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                 /* short read or no more work */
 302                 if ((ret != nr) || (len == 0))
 303                         break;
 304         }
 305 out:
 306         *ppos = ((loff_t)index << huge_page_shift(h)) + offset;
 307         return retval;
 308 }
 309
 310 static int hugetlbfs_write_begin(struct file *file,
 311                         struct address_space *mapping,
 312                         loff_t pos, unsigned len, unsigned flags,
 313                         struct page **pagep, void **fsdata)
 314 {
 315         return -EINVAL;
 316 }
 317
 318 static int hugetlbfs_write_end(struct file *file, struct address_space *mapping,
 319                         loff_t pos, unsigned len, unsigned copied,
 320                         struct page *page, void *fsdata)
 321 {
 322         BUG();
 323         return -EINVAL;
 324 }
 325
 326 static void truncate_huge_page(struct page *page)
 327 {
 328         cancel_dirty_page(page, /* No IO accounting for huge pages? */0);
 329         ClearPageUptodate(page);
 330         delete_from_page_cache(page);
 331 }
 332
 333 static void truncate_hugepages(struct inode *inode, loff_t lstart)
 334 {
 335         struct hstate *h = hstate_inode(inode);
 336         struct address_space *mapping = &inode->i_data;
 337         const pgoff_t start = lstart >> huge_page_shift(h);
 338         struct pagevec pvec;
 339         pgoff_t next;
 340         int i, freed = 0;
 341
 342         pagevec_init(&pvec, 0);
 343         next = start;
 344         while (1) {
 345                 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
 346                         if (next == start)
 347                                 break;
 348                         next = start;
 349                         continue;
 350                 }
 351
 352                 for (i = 0; i < pagevec_count(&pvec); ++i) {
 353                         struct page *page = pvec.pages[i];
 354
 355                         lock_page(page);
 356                         if (page->index > next)
 357                                 next = page->index;
 358                         ++next;
 359                         truncate_huge_page(page);
 360                         unlock_page(page);
 361                         freed++;
 362                 }
 363                 huge_pagevec_release(&pvec);
 364         }
 365         BUG_ON(!lstart && mapping->nrpages);
 366         hugetlb_unreserve_pages(inode, start, freed);
 367 }
 368
 369 static void hugetlbfs_evict_inode(struct inode *inode)
 370 {
 371         struct resv_map *resv_map;
 372
 373         truncate_hugepages(inode, 0);
 374         resv_map = (struct resv_map *)inode->i_mapping->private_data;
 375         /* root inode doesn't have the resv_map, so we should check it */
 376         if (resv_map)
 377                 resv_map_release(&resv_map->refs);
 378         clear_inode(inode);
 379 }
 380
 381 static inline void
 382 hugetlb_vmtruncate_list(struct rb_root *root, pgoff_t pgoff)
 383 {
 384         struct vm_area_struct *vma;
 385
 386         vma_interval_tree_foreach(vma, 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 interval 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, vma->vm_start + v_offset,
 401                                      vma->vm_end, NULL);
 402         }
 403 }
 404
 405 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
 406 {
 407         pgoff_t pgoff;
 408         struct address_space *mapping = inode->i_mapping;
 409         struct hstate *h = hstate_inode(inode);
 410
 411         BUG_ON(offset & ~huge_page_mask(h));
 412         pgoff = offset >> PAGE_SHIFT;
 413
 414         i_size_write(inode, offset);
 415         mutex_lock(&mapping->i_mmap_mutex);
 416         if (!RB_EMPTY_ROOT(&mapping->i_mmap))
 417                 hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff);
 418         mutex_unlock(&mapping->i_mmap_mutex);
 419         truncate_hugepages(inode, offset);
 420         return 0;
 421 }
 422
 423 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
 424 {
 425         struct inode *inode = dentry->d_inode;
 426         struct hstate *h = hstate_inode(inode);
 427         int error;
 428         unsigned int ia_valid = attr->ia_valid;
 429
 430         BUG_ON(!inode);
 431
 432         error = inode_change_ok(inode, attr);
 433         if (error)
 434                 return error;
 435
 436         if (ia_valid & ATTR_SIZE) {
 437                 error = -EINVAL;
 438                 if (attr->ia_size & ~huge_page_mask(h))
 439                         return -EINVAL;
 440                 error = hugetlb_vmtruncate(inode, attr->ia_size);
 441                 if (error)
 442                         return error;
 443         }
 444
 445         setattr_copy(inode, attr);
 446         mark_inode_dirty(inode);
 447         return 0;
 448 }
 449
 450 static struct inode *hugetlbfs_get_root(struct super_block *sb,
 451                                         struct hugetlbfs_config *config)
 452 {
 453         struct inode *inode;
 454
 455         inode = new_inode(sb);
 456         if (inode) {
 457                 struct hugetlbfs_inode_info *info;
 458                 inode->i_ino = get_next_ino();
 459                 inode->i_mode = S_IFDIR | config->mode;
 460                 inode->i_uid = config->uid;
 461                 inode->i_gid = config->gid;
 462                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 463                 info = HUGETLBFS_I(inode);
 464                 mpol_shared_policy_init(&info->policy, NULL);
 465                 inode->i_op = &hugetlbfs_dir_inode_operations;
 466                 inode->i_fop = &simple_dir_operations;
 467                 /* directory inodes start off with i_nlink == 2 (for "." entry) */
 468                 inc_nlink(inode);
 469                 lockdep_annotate_inode_mutex_key(inode);
 470         }
 471         return inode;
 472 }
 473
 474 /*
 475  * Hugetlbfs is not reclaimable; therefore its i_mmap_mutex will never
 476  * be taken from reclaim -- unlike regular filesystems. This needs an
 477  * annotation because huge_pmd_share() does an allocation under
 478  * i_mmap_mutex.
 479  */
 480 static struct lock_class_key hugetlbfs_i_mmap_mutex_key;
 481
 482 static struct inode *hugetlbfs_get_inode(struct super_block *sb,
 483                                         struct inode *dir,
 484                                         umode_t mode, dev_t dev)
 485 {
 486         struct inode *inode;
 487         struct resv_map *resv_map;
 488
 489         resv_map = resv_map_alloc();
 490         if (!resv_map)
 491                 return NULL;
 492
 493         inode = new_inode(sb);
 494         if (inode) {
 495                 struct hugetlbfs_inode_info *info;
 496                 inode->i_ino = get_next_ino();
 497                 inode_init_owner(inode, dir, mode);
 498                 lockdep_set_class(&inode->i_mapping->i_mmap_mutex,
 499                                 &hugetlbfs_i_mmap_mutex_key);
 500                 inode->i_mapping->a_ops = &hugetlbfs_aops;
 501                 inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info;
 502                 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 503                 inode->i_mapping->private_data = resv_map;
 504                 info = HUGETLBFS_I(inode);
 505                 /*
 506                  * The policy is initialized here even if we are creating a
 507                  * private inode because initialization simply creates an
 508                  * an empty rb tree and calls spin_lock_init(), later when we
 509                  * call mpol_free_shared_policy() it will just return because
 510                  * the rb tree will still be empty.
 511                  */
 512                 mpol_shared_policy_init(&info->policy, NULL);
 513                 switch (mode & S_IFMT) {
 514                 default:
 515                         init_special_inode(inode, mode, dev);
 516                         break;
 517                 case S_IFREG:
 518                         inode->i_op = &hugetlbfs_inode_operations;
 519                         inode->i_fop = &hugetlbfs_file_operations;
 520                         break;
 521                 case S_IFDIR:
 522                         inode->i_op = &hugetlbfs_dir_inode_operations;
 523                         inode->i_fop = &simple_dir_operations;
 524
 525                         /* directory inodes start off with i_nlink == 2 (for "." entry) */
 526                         inc_nlink(inode);
 527                         break;
 528                 case S_IFLNK:
 529                         inode->i_op = &page_symlink_inode_operations;
 530                         break;
 531                 }
 532                 lockdep_annotate_inode_mutex_key(inode);
 533         } else
 534                 kref_put(&resv_map->refs, resv_map_release);
 535
 536         return inode;
 537 }
 538
 539 /*
 540  * File creation. Allocate an inode, and we're done..
 541  */
 542 static int hugetlbfs_mknod(struct inode *dir,
 543                         struct dentry *dentry, umode_t mode, dev_t dev)
 544 {
 545         struct inode *inode;
 546         int error = -ENOSPC;
 547
 548         inode = hugetlbfs_get_inode(dir->i_sb, dir, mode, dev);
 549         if (inode) {
 550                 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 551                 d_instantiate(dentry, inode);
 552                 dget(dentry);   /* Extra count - pin the dentry in core */
 553                 error = 0;
 554         }
 555         return error;
 556 }
 557
 558 static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 559 {
 560         int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
 561         if (!retval)
 562                 inc_nlink(dir);
 563         return retval;
 564 }
 565
 566 static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl)
 567 {
 568         return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
 569 }
 570
 571 static int hugetlbfs_symlink(struct inode *dir,
 572                         struct dentry *dentry, const char *symname)
 573 {
 574         struct inode *inode;
 575         int error = -ENOSPC;
 576
 577         inode = hugetlbfs_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0);
 578         if (inode) {
 579                 int l = strlen(symname)+1;
 580                 error = page_symlink(inode, symname, l);
 581                 if (!error) {
 582                         d_instantiate(dentry, inode);
 583                         dget(dentry);
 584                 } else
 585                         iput(inode);
 586         }
 587         dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 588
 589         return error;
 590 }
 591
 592 /*
 593  * mark the head page dirty
 594  */
 595 static int hugetlbfs_set_page_dirty(struct page *page)
 596 {
 597         struct page *head = compound_head(page);
 598
 599         SetPageDirty(head);
 600         return 0;
 601 }
 602
 603 static int hugetlbfs_migrate_page(struct address_space *mapping,
 604                                 struct page *newpage, struct page *page,
 605                                 enum migrate_mode mode)
 606 {
 607         int rc;
 608
 609         rc = migrate_huge_page_move_mapping(mapping, newpage, page);
 610         if (rc != MIGRATEPAGE_SUCCESS)
 611                 return rc;
 612         migrate_page_copy(newpage, page);
 613
 614         return MIGRATEPAGE_SUCCESS;
 615 }
 616
 617 static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 618 {
 619         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
 620         struct hstate *h = hstate_inode(dentry->d_inode);
 621
 622         buf->f_type = HUGETLBFS_MAGIC;
 623         buf->f_bsize = huge_page_size(h);
 624         if (sbinfo) {
 625                 spin_lock(&sbinfo->stat_lock);
 626                 /* If no limits set, just report 0 for max/free/used
 627                  * blocks, like simple_statfs() */
 628                 if (sbinfo->spool) {
 629                         long free_pages;
 630
 631                         spin_lock(&sbinfo->spool->lock);
 632                         buf->f_blocks = sbinfo->spool->max_hpages;
 633                         free_pages = sbinfo->spool->max_hpages
 634                                 - sbinfo->spool->used_hpages;
 635                         buf->f_bavail = buf->f_bfree = free_pages;
 636                         spin_unlock(&sbinfo->spool->lock);
 637                         buf->f_files = sbinfo->max_inodes;
 638                         buf->f_ffree = sbinfo->free_inodes;
 639                 }
 640                 spin_unlock(&sbinfo->stat_lock);
 641         }
 642         buf->f_namelen = NAME_MAX;
 643         return 0;
 644 }
 645
 646 static void hugetlbfs_put_super(struct super_block *sb)
 647 {
 648         struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
 649
 650         if (sbi) {
 651                 sb->s_fs_info = NULL;
 652
 653                 if (sbi->spool)
 654                         hugepage_put_subpool(sbi->spool);
 655
 656                 kfree(sbi);
 657         }
 658 }
 659
 660 static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
 661 {
 662         if (sbinfo->free_inodes >= 0) {
 663                 spin_lock(&sbinfo->stat_lock);
 664                 if (unlikely(!sbinfo->free_inodes)) {
 665                         spin_unlock(&sbinfo->stat_lock);
 666                         return 0;
 667                 }
 668                 sbinfo->free_inodes--;
 669                 spin_unlock(&sbinfo->stat_lock);
 670         }
 671
 672         return 1;
 673 }
 674
 675 static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
 676 {
 677         if (sbinfo->free_inodes >= 0) {
 678                 spin_lock(&sbinfo->stat_lock);
 679                 sbinfo->free_inodes++;
 680                 spin_unlock(&sbinfo->stat_lock);
 681         }
 682 }
 683
 684
 685 static struct kmem_cache *hugetlbfs_inode_cachep;
 686
 687 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
 688 {
 689         struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
 690         struct hugetlbfs_inode_info *p;
 691
 692         if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
 693                 return NULL;
 694         p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL);
 695         if (unlikely(!p)) {
 696                 hugetlbfs_inc_free_inodes(sbinfo);
 697                 return NULL;
 698         }
 699         return &p->vfs_inode;
 700 }
 701
 702 static void hugetlbfs_i_callback(struct rcu_head *head)
 703 {
 704         struct inode *inode = container_of(head, struct inode, i_rcu);
 705         kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
 706 }
 707
 708 static void hugetlbfs_destroy_inode(struct inode *inode)
 709 {
 710         hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
 711         mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
 712         call_rcu(&inode->i_rcu, hugetlbfs_i_callback);
 713 }
 714
 715 static const struct address_space_operations hugetlbfs_aops = {
 716         .write_begin    = hugetlbfs_write_begin,
 717         .write_end      = hugetlbfs_write_end,
 718         .set_page_dirty = hugetlbfs_set_page_dirty,
 719         .migratepage    = hugetlbfs_migrate_page,
 720 };
 721
 722
 723 static void init_once(void *foo)
 724 {
 725         struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
 726
 727         inode_init_once(&ei->vfs_inode);
 728 }
 729
 730 const struct file_operations hugetlbfs_file_operations = {
 731         .read                   = hugetlbfs_read,
 732         .mmap                   = hugetlbfs_file_mmap,
 733         .fsync                  = noop_fsync,
 734         .get_unmapped_area      = hugetlb_get_unmapped_area,
 735         .llseek         = default_llseek,
 736 };
 737
 738 static const struct inode_operations hugetlbfs_dir_inode_operations = {
 739         .create         = hugetlbfs_create,
 740         .lookup         = simple_lookup,
 741         .link           = simple_link,
 742         .unlink         = simple_unlink,
 743         .symlink        = hugetlbfs_symlink,
 744         .mkdir          = hugetlbfs_mkdir,
 745         .rmdir          = simple_rmdir,
 746         .mknod          = hugetlbfs_mknod,
 747         .rename         = simple_rename,
 748         .setattr        = hugetlbfs_setattr,
 749 };
 750
 751 static const struct inode_operations hugetlbfs_inode_operations = {
 752         .setattr        = hugetlbfs_setattr,
 753 };
 754
 755 static const struct super_operations hugetlbfs_ops = {
 756         .alloc_inode    = hugetlbfs_alloc_inode,
 757         .destroy_inode  = hugetlbfs_destroy_inode,
 758         .evict_inode    = hugetlbfs_evict_inode,
 759         .statfs         = hugetlbfs_statfs,
 760         .put_super      = hugetlbfs_put_super,
 761         .show_options   = generic_show_options,
 762 };
 763
 764 static int
 765 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
 766 {
 767         char *p, *rest;
 768         substring_t args[MAX_OPT_ARGS];
 769         int option;
 770         unsigned long long size = 0;
 771         enum { NO_SIZE, SIZE_STD, SIZE_PERCENT } setsize = NO_SIZE;
 772
 773         if (!options)
 774                 return 0;
 775
 776         while ((p = strsep(&options, ",")) != NULL) {
 777                 int token;
 778                 if (!*p)
 779                         continue;
 780
 781                 token = match_token(p, tokens, args);
 782                 switch (token) {
 783                 case Opt_uid:
 784                         if (match_int(&args[0], &option))
 785                                 goto bad_val;
 786                         pconfig->uid = make_kuid(current_user_ns(), option);
 787                         if (!uid_valid(pconfig->uid))
 788                                 goto bad_val;
 789                         break;
 790
 791                 case Opt_gid:
 792                         if (match_int(&args[0], &option))
 793                                 goto bad_val;
 794                         pconfig->gid = make_kgid(current_user_ns(), option);
 795                         if (!gid_valid(pconfig->gid))
 796                                 goto bad_val;
 797                         break;
 798
 799                 case Opt_mode:
 800                         if (match_octal(&args[0], &option))
 801                                 goto bad_val;
 802                         pconfig->mode = option & 01777U;
 803                         break;
 804
 805                 case Opt_size: {
 806                         /* memparse() will accept a K/M/G without a digit */
 807                         if (!isdigit(*args[0].from))
 808                                 goto bad_val;
 809                         size = memparse(args[0].from, &rest);
 810                         setsize = SIZE_STD;
 811                         if (*rest == '%')
 812                                 setsize = SIZE_PERCENT;
 813                         break;
 814                 }
 815
 816                 case Opt_nr_inodes:
 817                         /* memparse() will accept a K/M/G without a digit */
 818                         if (!isdigit(*args[0].from))
 819                                 goto bad_val;
 820                         pconfig->nr_inodes = memparse(args[0].from, &rest);
 821                         break;
 822
 823                 case Opt_pagesize: {
 824                         unsigned long ps;
 825                         ps = memparse(args[0].from, &rest);
 826                         pconfig->hstate = size_to_hstate(ps);
 827                         if (!pconfig->hstate) {
 828                                 pr_err("Unsupported page size %lu MB\n",
 829                                         ps >> 20);
 830                                 return -EINVAL;
 831                         }
 832                         break;
 833                 }
 834
 835                 default:
 836                         pr_err("Bad mount option: \"%s\"\n", 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         pr_err("Bad value '%s' for mount option '%s'\n", args[0].from, p);
 857         return -EINVAL;
 858 }
 859
 860 static int
 861 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
 862 {
 863         int ret;
 864         struct hugetlbfs_config config;
 865         struct hugetlbfs_sb_info *sbinfo;
 866
 867         save_mount_options(sb, data);
 868
 869         config.nr_blocks = -1; /* No limit on size by default */
 870         config.nr_inodes = -1; /* No limit on number of inodes by default */
 871         config.uid = current_fsuid();
 872         config.gid = current_fsgid();
 873         config.mode = 0755;
 874         config.hstate = &default_hstate;
 875         ret = hugetlbfs_parse_options(data, &config);
 876         if (ret)
 877                 return ret;
 878
 879         sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
 880         if (!sbinfo)
 881                 return -ENOMEM;
 882         sb->s_fs_info = sbinfo;
 883         sbinfo->hstate = config.hstate;
 884         spin_lock_init(&sbinfo->stat_lock);
 885         sbinfo->max_inodes = config.nr_inodes;
 886         sbinfo->free_inodes = config.nr_inodes;
 887         sbinfo->spool = NULL;
 888         if (config.nr_blocks != -1) {
 889                 sbinfo->spool = hugepage_new_subpool(config.nr_blocks);
 890                 if (!sbinfo->spool)
 891                         goto out_free;
 892         }
 893         sb->s_maxbytes = MAX_LFS_FILESIZE;
 894         sb->s_blocksize = huge_page_size(config.hstate);
 895         sb->s_blocksize_bits = huge_page_shift(config.hstate);
 896         sb->s_magic = HUGETLBFS_MAGIC;
 897         sb->s_op = &hugetlbfs_ops;
 898         sb->s_time_gran = 1;
 899         sb->s_root = d_make_root(hugetlbfs_get_root(sb, &config));
 900         if (!sb->s_root)
 901                 goto out_free;
 902         return 0;
 903 out_free:
 904         kfree(sbinfo->spool);
 905         kfree(sbinfo);
 906         return -ENOMEM;
 907 }
 908
 909 static struct dentry *hugetlbfs_mount(struct file_system_type *fs_type,
 910         int flags, const char *dev_name, void *data)
 911 {
 912         return mount_nodev(fs_type, flags, data, hugetlbfs_fill_super);
 913 }
 914
 915 static struct file_system_type hugetlbfs_fs_type = {
 916         .name           = "hugetlbfs",
 917         .mount          = hugetlbfs_mount,
 918         .kill_sb        = kill_litter_super,
 919 };
 920 MODULE_ALIAS_FS("hugetlbfs");
 921
 922 static struct vfsmount *hugetlbfs_vfsmount[HUGE_MAX_HSTATE];
 923
 924 static int can_do_hugetlb_shm(void)
 925 {
 926         kgid_t shm_group;
 927         shm_group = make_kgid(&init_user_ns, sysctl_hugetlb_shm_group);
 928         return capable(CAP_IPC_LOCK) || in_group_p(shm_group);
 929 }
 930
 931 static int get_hstate_idx(int page_size_log)
 932 {
 933         struct hstate *h = hstate_sizelog(page_size_log);
 934
 935         if (!h)
 936                 return -1;
 937         return h - hstates;
 938 }
 939
 940 static const struct dentry_operations anon_ops = {
 941         .d_dname = simple_dname
 942 };
 943
 944 /*
 945  * Note that size should be aligned to proper hugepage size in caller side,
 946  * otherwise hugetlb_reserve_pages reserves one less hugepages than intended.
 947  */
 948 struct file *hugetlb_file_setup(const char *name, size_t size,
 949                                 vm_flags_t acctflag, struct user_struct **user,
 950                                 int creat_flags, int page_size_log)
 951 {
 952         struct file *file = ERR_PTR(-ENOMEM);
 953         struct inode *inode;
 954         struct path path;
 955         struct super_block *sb;
 956         struct qstr quick_string;
 957         int hstate_idx;
 958
 959         hstate_idx = get_hstate_idx(page_size_log);
 960         if (hstate_idx < 0)
 961                 return ERR_PTR(-ENODEV);
 962
 963         *user = NULL;
 964         if (!hugetlbfs_vfsmount[hstate_idx])
 965                 return ERR_PTR(-ENOENT);
 966
 967         if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) {
 968                 *user = current_user();
 969                 if (user_shm_lock(size, *user)) {
 970                         task_lock(current);
 971                         pr_warn_once("%s (%d): Using mlock ulimits for SHM_HUGETLB is deprecated\n",
 972                                 current->comm, current->pid);
 973                         task_unlock(current);
 974                 } else {
 975                         *user = NULL;
 976                         return ERR_PTR(-EPERM);
 977                 }
 978         }
 979
 980         sb = hugetlbfs_vfsmount[hstate_idx]->mnt_sb;
 981         quick_string.name = name;
 982         quick_string.len = strlen(quick_string.name);
 983         quick_string.hash = 0;
 984         path.dentry = d_alloc_pseudo(sb, &quick_string);
 985         if (!path.dentry)
 986                 goto out_shm_unlock;
 987
 988         d_set_d_op(path.dentry, &anon_ops);
 989         path.mnt = mntget(hugetlbfs_vfsmount[hstate_idx]);
 990         file = ERR_PTR(-ENOSPC);
 991         inode = hugetlbfs_get_inode(sb, NULL, S_IFREG | S_IRWXUGO, 0);
 992         if (!inode)
 993                 goto out_dentry;
 994
 995         file = ERR_PTR(-ENOMEM);
 996         if (hugetlb_reserve_pages(inode, 0,
 997                         size >> huge_page_shift(hstate_inode(inode)), NULL,
 998                         acctflag))
 999                 goto out_inode;
1000
1001         d_instantiate(path.dentry, inode);
1002         inode->i_size = size;
1003         clear_nlink(inode);
1004
1005         file = alloc_file(&path, FMODE_WRITE | FMODE_READ,
1006                         &hugetlbfs_file_operations);
1007         if (IS_ERR(file))
1008                 goto out_dentry; /* inode is already attached */
1009
1010         return file;
1011
1012 out_inode:
1013         iput(inode);
1014 out_dentry:
1015         path_put(&path);
1016 out_shm_unlock:
1017         if (*user) {
1018                 user_shm_unlock(size, *user);
1019                 *user = NULL;
1020         }
1021         return file;
1022 }
1023
1024 static int __init init_hugetlbfs_fs(void)
1025 {
1026         struct hstate *h;
1027         int error;
1028         int i;
1029
1030         if (!hugepages_supported()) {
1031                 pr_info("disabling because there are no supported hugepage sizes\n");
1032                 return -ENOTSUPP;
1033         }
1034
1035         error = bdi_init(&hugetlbfs_backing_dev_info);
1036         if (error)
1037                 return error;
1038
1039         error = -ENOMEM;
1040         hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
1041                                         sizeof(struct hugetlbfs_inode_info),
1042                                         0, 0, init_once);
1043         if (hugetlbfs_inode_cachep == NULL)
1044                 goto out2;
1045
1046         error = register_filesystem(&hugetlbfs_fs_type);
1047         if (error)
1048                 goto out;
1049
1050         i = 0;
1051         for_each_hstate(h) {
1052                 char buf[50];
1053                 unsigned ps_kb = 1U << (h->order + PAGE_SHIFT - 10);
1054
1055                 snprintf(buf, sizeof(buf), "pagesize=%uK", ps_kb);
1056                 hugetlbfs_vfsmount[i] = kern_mount_data(&hugetlbfs_fs_type,
1057                                                         buf);
1058
1059                 if (IS_ERR(hugetlbfs_vfsmount[i])) {
1060                         pr_err("Cannot mount internal hugetlbfs for "
1061                                 "page size %uK", ps_kb);
1062                         error = PTR_ERR(hugetlbfs_vfsmount[i]);
1063                         hugetlbfs_vfsmount[i] = NULL;
1064                 }
1065                 i++;
1066         }
1067         /* Non default hstates are optional */
1068         if (!IS_ERR_OR_NULL(hugetlbfs_vfsmount[default_hstate_idx]))
1069                 return 0;
1070
1071  out:
1072         kmem_cache_destroy(hugetlbfs_inode_cachep);
1073  out2:
1074         bdi_destroy(&hugetlbfs_backing_dev_info);
1075         return error;
1076 }
1077
1078 static void __exit exit_hugetlbfs_fs(void)
1079 {
1080         struct hstate *h;
1081         int i;
1082
1083
1084         /*
1085          * Make sure all delayed rcu free inodes are flushed before we
1086          * destroy cache.
1087          */
1088         rcu_barrier();
1089         kmem_cache_destroy(hugetlbfs_inode_cachep);
1090         i = 0;
1091         for_each_hstate(h)
1092                 kern_unmount(hugetlbfs_vfsmount[i++]);
1093         unregister_filesystem(&hugetlbfs_fs_type);
1094         bdi_destroy(&hugetlbfs_backing_dev_info);
1095 }
1096
1097 module_init(init_hugetlbfs_fs)
1098 module_exit(exit_hugetlbfs_fs)
1099
1100 MODULE_LICENSE("GPL");