linux/fs/hugetlbfs/inode.c
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   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
  40static const struct super_operations hugetlbfs_ops;
  41static const struct address_space_operations hugetlbfs_aops;
  42const struct file_operations hugetlbfs_file_operations;
  43static const struct inode_operations hugetlbfs_dir_inode_operations;
  44static const struct inode_operations hugetlbfs_inode_operations;
  45
  46struct 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
  55struct hugetlbfs_inode_info {
  56        struct shared_policy policy;
  57        struct inode vfs_inode;
  58};
  59
  60static inline struct hugetlbfs_inode_info *HUGETLBFS_I(struct inode *inode)
  61{
  62        return container_of(inode, struct hugetlbfs_inode_info, vfs_inode);
  63}
  64
  65static 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
  71int sysctl_hugetlb_shm_group;
  72
  73enum {
  74        Opt_size, Opt_nr_inodes,
  75        Opt_mode, Opt_uid, Opt_gid,
  76        Opt_pagesize,
  77        Opt_err,
  78};
  79
  80static 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
  90static 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
 100static 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;
 139out:
 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
 150static unsigned long
 151hugetlb_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
 188static int
 189hugetlbfs_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 */
 231static 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        }
 305out:
 306        *ppos = ((loff_t)index << huge_page_shift(h)) + offset;
 307        return retval;
 308}
 309
 310static 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
 318static 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
 326static 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
 333static 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
 369static 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
 381static inline void
 382hugetlb_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
 405static 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        i_mmap_lock_write(mapping);
 416        if (!RB_EMPTY_ROOT(&mapping->i_mmap))
 417                hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff);
 418        i_mmap_unlock_write(mapping);
 419        truncate_hugepages(inode, offset);
 420        return 0;
 421}
 422
 423static 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
 450static 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_rwsem 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_rwsem.
 479 */
 480static struct lock_class_key hugetlbfs_i_mmap_rwsem_key;
 481
 482static 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_rwsem,
 499                                &hugetlbfs_i_mmap_rwsem_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 */
 542static 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
 558static 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
 566static 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
 571static 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 */
 595static 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
 603static 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
 617static 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
 646static 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
 660static 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
 675static 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
 685static struct kmem_cache *hugetlbfs_inode_cachep;
 686
 687static 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
 702static 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
 708static 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
 715static 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
 723static 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
 730const 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
 738static 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
 751static const struct inode_operations hugetlbfs_inode_operations = {
 752        .setattr        = hugetlbfs_setattr,
 753};
 754
 755static 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
 764static int
 765hugetlbfs_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
 855bad_val:
 856        pr_err("Bad value '%s' for mount option '%s'\n", args[0].from, p);
 857        return -EINVAL;
 858}
 859
 860static int
 861hugetlbfs_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;
 903out_free:
 904        kfree(sbinfo->spool);
 905        kfree(sbinfo);
 906        return -ENOMEM;
 907}
 908
 909static 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
 915static struct file_system_type hugetlbfs_fs_type = {
 916        .name           = "hugetlbfs",
 917        .mount          = hugetlbfs_mount,
 918        .kill_sb        = kill_litter_super,
 919};
 920MODULE_ALIAS_FS("hugetlbfs");
 921
 922static struct vfsmount *hugetlbfs_vfsmount[HUGE_MAX_HSTATE];
 923
 924static 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
 931static 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
 940static 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 */
 948struct 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
1012out_inode:
1013        iput(inode);
1014out_dentry:
1015        path_put(&path);
1016out_shm_unlock:
1017        if (*user) {
1018                user_shm_unlock(size, *user);
1019                *user = NULL;
1020        }
1021        return file;
1022}
1023
1024static 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
1078static 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
1097module_init(init_hugetlbfs_fs)
1098module_exit(exit_hugetlbfs_fs)
1099
1100MODULE_LICENSE("GPL");
1101
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