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#include <linux/module.h>
  10#include <linux/thread_info.h>
  11#include <asm/current.h>
  12#include <linux/sched.h>                /* remove ASAP */
  13#include <linux/fs.h>
  14#include <linux/mount.h>
  15#include <linux/file.h>
  16#include <linux/kernel.h>
  17#include <linux/writeback.h>
  18#include <linux/pagemap.h>
  19#include <linux/highmem.h>
  20#include <linux/init.h>
  21#include <linux/string.h>
  22#include <linux/capability.h>
  23#include <linux/ctype.h>
  24#include <linux/backing-dev.h>
  25#include <linux/hugetlb.h>
  26#include <linux/pagevec.h>
  27#include <linux/parser.h>
  28#include <linux/mman.h>
  29#include <linux/slab.h>
  30#include <linux/dnotify.h>
  31#include <linux/statfs.h>
  32#include <linux/security.h>
  33#include <linux/magic.h>
  34#include <linux/migrate.h>
  35
  36#include <asm/uaccess.h>
  37
  38static const struct super_operations hugetlbfs_ops;
  39static const struct address_space_operations hugetlbfs_aops;
  40const struct file_operations hugetlbfs_file_operations;
  41static const struct inode_operations hugetlbfs_dir_inode_operations;
  42static const struct inode_operations hugetlbfs_inode_operations;
  43
  44struct hugetlbfs_config {
  45        kuid_t   uid;
  46        kgid_t   gid;
  47        umode_t mode;
  48        long    nr_blocks;
  49        long    nr_inodes;
  50        struct hstate *hstate;
  51};
  52
  53struct hugetlbfs_inode_info {
  54        struct shared_policy policy;
  55        struct inode vfs_inode;
  56};
  57
  58static inline struct hugetlbfs_inode_info *HUGETLBFS_I(struct inode *inode)
  59{
  60        return container_of(inode, struct hugetlbfs_inode_info, vfs_inode);
  61}
  62
  63static struct backing_dev_info hugetlbfs_backing_dev_info = {
  64        .name           = "hugetlbfs",
  65        .ra_pages       = 0,    /* No readahead */
  66        .capabilities   = BDI_CAP_NO_ACCT_AND_WRITEBACK,
  67};
  68
  69int sysctl_hugetlb_shm_group;
  70
  71enum {
  72        Opt_size, Opt_nr_inodes,
  73        Opt_mode, Opt_uid, Opt_gid,
  74        Opt_pagesize,
  75        Opt_err,
  76};
  77
  78static const match_table_t tokens = {
  79        {Opt_size,      "size=%s"},
  80        {Opt_nr_inodes, "nr_inodes=%s"},
  81        {Opt_mode,      "mode=%o"},
  82        {Opt_uid,       "uid=%u"},
  83        {Opt_gid,       "gid=%u"},
  84        {Opt_pagesize,  "pagesize=%s"},
  85        {Opt_err,       NULL},
  86};
  87
  88static void huge_pagevec_release(struct pagevec *pvec)
  89{
  90        int i;
  91
  92        for (i = 0; i < pagevec_count(pvec); ++i)
  93                put_page(pvec->pages[i]);
  94
  95        pagevec_reinit(pvec);
  96}
  97
  98static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
  99{
 100        struct inode *inode = file_inode(file);
 101        loff_t len, vma_len;
 102        int ret;
 103        struct hstate *h = hstate_file(file);
 104
 105        /*
 106         * vma address alignment (but not the pgoff alignment) has
 107         * already been checked by prepare_hugepage_range.  If you add
 108         * any error returns here, do so after setting VM_HUGETLB, so
 109         * is_vm_hugetlb_page tests below unmap_region go the right
 110         * way when do_mmap_pgoff unwinds (may be important on powerpc
 111         * and ia64).
 112         */
 113        vma->vm_flags |= VM_HUGETLB | VM_DONTEXPAND;
 114        vma->vm_ops = &hugetlb_vm_ops;
 115
 116        if (vma->vm_pgoff & (~huge_page_mask(h) >> PAGE_SHIFT))
 117                return -EINVAL;
 118
 119        vma_len = (loff_t)(vma->vm_end - vma->vm_start);
 120
 121        mutex_lock(&inode->i_mutex);
 122        file_accessed(file);
 123
 124        ret = -ENOMEM;
 125        len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
 126
 127        if (hugetlb_reserve_pages(inode,
 128                                vma->vm_pgoff >> huge_page_order(h),
 129                                len >> huge_page_shift(h), vma,
 130                                vma->vm_flags))
 131                goto out;
 132
 133        ret = 0;
 134        hugetlb_prefault_arch_hook(vma->vm_mm);
 135        if (vma->vm_flags & VM_WRITE && inode->i_size < len)
 136                inode->i_size = len;
 137out:
 138        mutex_unlock(&inode->i_mutex);
 139
 140        return ret;
 141}
 142
 143/*
 144 * Called under down_write(mmap_sem).
 145 */
 146
 147#ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
 148static unsigned long
 149hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 150                unsigned long len, unsigned long pgoff, unsigned long flags)
 151{
 152        struct mm_struct *mm = current->mm;
 153        struct vm_area_struct *vma;
 154        struct hstate *h = hstate_file(file);
 155        struct vm_unmapped_area_info info;
 156
 157        if (len & ~huge_page_mask(h))
 158                return -EINVAL;
 159        if (len > TASK_SIZE)
 160                return -ENOMEM;
 161
 162        if (flags & MAP_FIXED) {
 163                if (prepare_hugepage_range(file, addr, len))
 164                        return -EINVAL;
 165                return addr;
 166        }
 167
 168        if (addr) {
 169                addr = ALIGN(addr, huge_page_size(h));
 170                vma = find_vma(mm, addr);
 171                if (TASK_SIZE - len >= addr &&
 172                    (!vma || addr + len <= vma->vm_start))
 173                        return addr;
 174        }
 175
 176        info.flags = 0;
 177        info.length = len;
 178        info.low_limit = TASK_UNMAPPED_BASE;
 179        info.high_limit = TASK_SIZE;
 180        info.align_mask = PAGE_MASK & ~huge_page_mask(h);
 181        info.align_offset = 0;
 182        return vm_unmapped_area(&info);
 183}
 184#endif
 185
 186static int
 187hugetlbfs_read_actor(struct page *page, unsigned long offset,
 188                        char __user *buf, unsigned long count,
 189                        unsigned long size)
 190{
 191        char *kaddr;
 192        unsigned long left, copied = 0;
 193        int i, chunksize;
 194
 195        if (size > count)
 196                size = count;
 197
 198        /* Find which 4k chunk and offset with in that chunk */
 199        i = offset >> PAGE_CACHE_SHIFT;
 200        offset = offset & ~PAGE_CACHE_MASK;
 201
 202        while (size) {
 203                chunksize = PAGE_CACHE_SIZE;
 204                if (offset)
 205                        chunksize -= offset;
 206                if (chunksize > size)
 207                        chunksize = size;
 208                kaddr = kmap(&page[i]);
 209                left = __copy_to_user(buf, kaddr + offset, chunksize);
 210                kunmap(&page[i]);
 211                if (left) {
 212                        copied += (chunksize - left);
 213                        break;
 214                }
 215                offset = 0;
 216                size -= chunksize;
 217                buf += chunksize;
 218                copied += chunksize;
 219                i++;
 220        }
 221        return copied ? copied : -EFAULT;
 222}
 223
 224/*
 225 * Support for read() - Find the page attached to f_mapping and copy out the
 226 * data. Its *very* similar to do_generic_mapping_read(), we can't use that
 227 * since it has PAGE_CACHE_SIZE assumptions.
 228 */
 229static ssize_t hugetlbfs_read(struct file *filp, char __user *buf,
 230                              size_t len, loff_t *ppos)
 231{
 232        struct hstate *h = hstate_file(filp);
 233        struct address_space *mapping = filp->f_mapping;
 234        struct inode *inode = mapping->host;
 235        unsigned long index = *ppos >> huge_page_shift(h);
 236        unsigned long offset = *ppos & ~huge_page_mask(h);
 237        unsigned long end_index;
 238        loff_t isize;
 239        ssize_t retval = 0;
 240
 241        /* validate length */
 242        if (len == 0)
 243                goto out;
 244
 245        for (;;) {
 246                struct page *page;
 247                unsigned long nr, ret;
 248                int ra;
 249
 250                /* nr is the maximum number of bytes to copy from this page */
 251                nr = huge_page_size(h);
 252                isize = i_size_read(inode);
 253                if (!isize)
 254                        goto out;
 255                end_index = (isize - 1) >> huge_page_shift(h);
 256                if (index >= end_index) {
 257                        if (index > end_index)
 258                                goto out;
 259                        nr = ((isize - 1) & ~huge_page_mask(h)) + 1;
 260                        if (nr <= offset)
 261                                goto out;
 262                }
 263                nr = nr - offset;
 264
 265                /* Find the page */
 266                page = find_lock_page(mapping, index);
 267                if (unlikely(page == NULL)) {
 268                        /*
 269                         * We have a HOLE, zero out the user-buffer for the
 270                         * length of the hole or request.
 271                         */
 272                        ret = len < nr ? len : nr;
 273                        if (clear_user(buf, ret))
 274                                ra = -EFAULT;
 275                        else
 276                                ra = 0;
 277                } else {
 278                        unlock_page(page);
 279
 280                        /*
 281                         * We have the page, copy it to user space buffer.
 282                         */
 283                        ra = hugetlbfs_read_actor(page, offset, buf, len, nr);
 284                        ret = ra;
 285                        page_cache_release(page);
 286                }
 287                if (ra < 0) {
 288                        if (retval == 0)
 289                                retval = ra;
 290                        goto out;
 291                }
 292
 293                offset += ret;
 294                retval += ret;
 295                len -= ret;
 296                index += offset >> huge_page_shift(h);
 297                offset &= ~huge_page_mask(h);
 298
 299                /* short read or no more work */
 300                if ((ret != nr) || (len == 0))
 301                        break;
 302        }
 303out:
 304        *ppos = ((loff_t)index << huge_page_shift(h)) + offset;
 305        return retval;
 306}
 307
 308static int hugetlbfs_write_begin(struct file *file,
 309                        struct address_space *mapping,
 310                        loff_t pos, unsigned len, unsigned flags,
 311                        struct page **pagep, void **fsdata)
 312{
 313        return -EINVAL;
 314}
 315
 316static int hugetlbfs_write_end(struct file *file, struct address_space *mapping,
 317                        loff_t pos, unsigned len, unsigned copied,
 318                        struct page *page, void *fsdata)
 319{
 320        BUG();
 321        return -EINVAL;
 322}
 323
 324static void truncate_huge_page(struct page *page)
 325{
 326        cancel_dirty_page(page, /* No IO accounting for huge pages? */0);
 327        ClearPageUptodate(page);
 328        delete_from_page_cache(page);
 329}
 330
 331static void truncate_hugepages(struct inode *inode, loff_t lstart)
 332{
 333        struct hstate *h = hstate_inode(inode);
 334        struct address_space *mapping = &inode->i_data;
 335        const pgoff_t start = lstart >> huge_page_shift(h);
 336        struct pagevec pvec;
 337        pgoff_t next;
 338        int i, freed = 0;
 339
 340        pagevec_init(&pvec, 0);
 341        next = start;
 342        while (1) {
 343                if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
 344                        if (next == start)
 345                                break;
 346                        next = start;
 347                        continue;
 348                }
 349
 350                for (i = 0; i < pagevec_count(&pvec); ++i) {
 351                        struct page *page = pvec.pages[i];
 352
 353                        lock_page(page);
 354                        if (page->index > next)
 355                                next = page->index;
 356                        ++next;
 357                        truncate_huge_page(page);
 358                        unlock_page(page);
 359                        freed++;
 360                }
 361                huge_pagevec_release(&pvec);
 362        }
 363        BUG_ON(!lstart && mapping->nrpages);
 364        hugetlb_unreserve_pages(inode, start, freed);
 365}
 366
 367static void hugetlbfs_evict_inode(struct inode *inode)
 368{
 369        truncate_hugepages(inode, 0);
 370        clear_inode(inode);
 371}
 372
 373static inline void
 374hugetlb_vmtruncate_list(struct rb_root *root, pgoff_t pgoff)
 375{
 376        struct vm_area_struct *vma;
 377
 378        vma_interval_tree_foreach(vma, root, pgoff, ULONG_MAX) {
 379                unsigned long v_offset;
 380
 381                /*
 382                 * Can the expression below overflow on 32-bit arches?
 383                 * No, because the interval tree returns us only those vmas
 384                 * which overlap the truncated area starting at pgoff,
 385                 * and no vma on a 32-bit arch can span beyond the 4GB.
 386                 */
 387                if (vma->vm_pgoff < pgoff)
 388                        v_offset = (pgoff - vma->vm_pgoff) << PAGE_SHIFT;
 389                else
 390                        v_offset = 0;
 391
 392                unmap_hugepage_range(vma, vma->vm_start + v_offset,
 393                                     vma->vm_end, NULL);
 394        }
 395}
 396
 397static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
 398{
 399        pgoff_t pgoff;
 400        struct address_space *mapping = inode->i_mapping;
 401        struct hstate *h = hstate_inode(inode);
 402
 403        BUG_ON(offset & ~huge_page_mask(h));
 404        pgoff = offset >> PAGE_SHIFT;
 405
 406        i_size_write(inode, offset);
 407        mutex_lock(&mapping->i_mmap_mutex);
 408        if (!RB_EMPTY_ROOT(&mapping->i_mmap))
 409                hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff);
 410        mutex_unlock(&mapping->i_mmap_mutex);
 411        truncate_hugepages(inode, offset);
 412        return 0;
 413}
 414
 415static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
 416{
 417        struct inode *inode = dentry->d_inode;
 418        struct hstate *h = hstate_inode(inode);
 419        int error;
 420        unsigned int ia_valid = attr->ia_valid;
 421
 422        BUG_ON(!inode);
 423
 424        error = inode_change_ok(inode, attr);
 425        if (error)
 426                return error;
 427
 428        if (ia_valid & ATTR_SIZE) {
 429                error = -EINVAL;
 430                if (attr->ia_size & ~huge_page_mask(h))
 431                        return -EINVAL;
 432                error = hugetlb_vmtruncate(inode, attr->ia_size);
 433                if (error)
 434                        return error;
 435        }
 436
 437        setattr_copy(inode, attr);
 438        mark_inode_dirty(inode);
 439        return 0;
 440}
 441
 442static struct inode *hugetlbfs_get_root(struct super_block *sb,
 443                                        struct hugetlbfs_config *config)
 444{
 445        struct inode *inode;
 446
 447        inode = new_inode(sb);
 448        if (inode) {
 449                struct hugetlbfs_inode_info *info;
 450                inode->i_ino = get_next_ino();
 451                inode->i_mode = S_IFDIR | config->mode;
 452                inode->i_uid = config->uid;
 453                inode->i_gid = config->gid;
 454                inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 455                info = HUGETLBFS_I(inode);
 456                mpol_shared_policy_init(&info->policy, NULL);
 457                inode->i_op = &hugetlbfs_dir_inode_operations;
 458                inode->i_fop = &simple_dir_operations;
 459                /* directory inodes start off with i_nlink == 2 (for "." entry) */
 460                inc_nlink(inode);
 461                lockdep_annotate_inode_mutex_key(inode);
 462        }
 463        return inode;
 464}
 465
 466/*
 467 * Hugetlbfs is not reclaimable; therefore its i_mmap_mutex will never
 468 * be taken from reclaim -- unlike regular filesystems. This needs an
 469 * annotation because huge_pmd_share() does an allocation under
 470 * i_mmap_mutex.
 471 */
 472struct lock_class_key hugetlbfs_i_mmap_mutex_key;
 473
 474static struct inode *hugetlbfs_get_inode(struct super_block *sb,
 475                                        struct inode *dir,
 476                                        umode_t mode, dev_t dev)
 477{
 478        struct inode *inode;
 479
 480        inode = new_inode(sb);
 481        if (inode) {
 482                struct hugetlbfs_inode_info *info;
 483                inode->i_ino = get_next_ino();
 484                inode_init_owner(inode, dir, mode);
 485                lockdep_set_class(&inode->i_mapping->i_mmap_mutex,
 486                                &hugetlbfs_i_mmap_mutex_key);
 487                inode->i_mapping->a_ops = &hugetlbfs_aops;
 488                inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info;
 489                inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 490                INIT_LIST_HEAD(&inode->i_mapping->private_list);
 491                info = HUGETLBFS_I(inode);
 492                /*
 493                 * The policy is initialized here even if we are creating a
 494                 * private inode because initialization simply creates an
 495                 * an empty rb tree and calls spin_lock_init(), later when we
 496                 * call mpol_free_shared_policy() it will just return because
 497                 * the rb tree will still be empty.
 498                 */
 499                mpol_shared_policy_init(&info->policy, NULL);
 500                switch (mode & S_IFMT) {
 501                default:
 502                        init_special_inode(inode, mode, dev);
 503                        break;
 504                case S_IFREG:
 505                        inode->i_op = &hugetlbfs_inode_operations;
 506                        inode->i_fop = &hugetlbfs_file_operations;
 507                        break;
 508                case S_IFDIR:
 509                        inode->i_op = &hugetlbfs_dir_inode_operations;
 510                        inode->i_fop = &simple_dir_operations;
 511
 512                        /* directory inodes start off with i_nlink == 2 (for "." entry) */
 513                        inc_nlink(inode);
 514                        break;
 515                case S_IFLNK:
 516                        inode->i_op = &page_symlink_inode_operations;
 517                        break;
 518                }
 519                lockdep_annotate_inode_mutex_key(inode);
 520        }
 521        return inode;
 522}
 523
 524/*
 525 * File creation. Allocate an inode, and we're done..
 526 */
 527static int hugetlbfs_mknod(struct inode *dir,
 528                        struct dentry *dentry, umode_t mode, dev_t dev)
 529{
 530        struct inode *inode;
 531        int error = -ENOSPC;
 532
 533        inode = hugetlbfs_get_inode(dir->i_sb, dir, mode, dev);
 534        if (inode) {
 535                dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 536                d_instantiate(dentry, inode);
 537                dget(dentry);   /* Extra count - pin the dentry in core */
 538                error = 0;
 539        }
 540        return error;
 541}
 542
 543static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 544{
 545        int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
 546        if (!retval)
 547                inc_nlink(dir);
 548        return retval;
 549}
 550
 551static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl)
 552{
 553        return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
 554}
 555
 556static int hugetlbfs_symlink(struct inode *dir,
 557                        struct dentry *dentry, const char *symname)
 558{
 559        struct inode *inode;
 560        int error = -ENOSPC;
 561
 562        inode = hugetlbfs_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0);
 563        if (inode) {
 564                int l = strlen(symname)+1;
 565                error = page_symlink(inode, symname, l);
 566                if (!error) {
 567                        d_instantiate(dentry, inode);
 568                        dget(dentry);
 569                } else
 570                        iput(inode);
 571        }
 572        dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 573
 574        return error;
 575}
 576
 577/*
 578 * mark the head page dirty
 579 */
 580static int hugetlbfs_set_page_dirty(struct page *page)
 581{
 582        struct page *head = compound_head(page);
 583
 584        SetPageDirty(head);
 585        return 0;
 586}
 587
 588static int hugetlbfs_migrate_page(struct address_space *mapping,
 589                                struct page *newpage, struct page *page,
 590                                enum migrate_mode mode)
 591{
 592        int rc;
 593
 594        rc = migrate_huge_page_move_mapping(mapping, newpage, page);
 595        if (rc != MIGRATEPAGE_SUCCESS)
 596                return rc;
 597        migrate_page_copy(newpage, page);
 598
 599        return MIGRATEPAGE_SUCCESS;
 600}
 601
 602static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 603{
 604        struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
 605        struct hstate *h = hstate_inode(dentry->d_inode);
 606
 607        buf->f_type = HUGETLBFS_MAGIC;
 608        buf->f_bsize = huge_page_size(h);
 609        if (sbinfo) {
 610                spin_lock(&sbinfo->stat_lock);
 611                /* If no limits set, just report 0 for max/free/used
 612                 * blocks, like simple_statfs() */
 613                if (sbinfo->spool) {
 614                        long free_pages;
 615
 616                        spin_lock(&sbinfo->spool->lock);
 617                        buf->f_blocks = sbinfo->spool->max_hpages;
 618                        free_pages = sbinfo->spool->max_hpages
 619                                - sbinfo->spool->used_hpages;
 620                        buf->f_bavail = buf->f_bfree = free_pages;
 621                        spin_unlock(&sbinfo->spool->lock);
 622                        buf->f_files = sbinfo->max_inodes;
 623                        buf->f_ffree = sbinfo->free_inodes;
 624                }
 625                spin_unlock(&sbinfo->stat_lock);
 626        }
 627        buf->f_namelen = NAME_MAX;
 628        return 0;
 629}
 630
 631static void hugetlbfs_put_super(struct super_block *sb)
 632{
 633        struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
 634
 635        if (sbi) {
 636                sb->s_fs_info = NULL;
 637
 638                if (sbi->spool)
 639                        hugepage_put_subpool(sbi->spool);
 640
 641                kfree(sbi);
 642        }
 643}
 644
 645static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
 646{
 647        if (sbinfo->free_inodes >= 0) {
 648                spin_lock(&sbinfo->stat_lock);
 649                if (unlikely(!sbinfo->free_inodes)) {
 650                        spin_unlock(&sbinfo->stat_lock);
 651                        return 0;
 652                }
 653                sbinfo->free_inodes--;
 654                spin_unlock(&sbinfo->stat_lock);
 655        }
 656
 657        return 1;
 658}
 659
 660static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
 661{
 662        if (sbinfo->free_inodes >= 0) {
 663                spin_lock(&sbinfo->stat_lock);
 664                sbinfo->free_inodes++;
 665                spin_unlock(&sbinfo->stat_lock);
 666        }
 667}
 668
 669
 670static struct kmem_cache *hugetlbfs_inode_cachep;
 671
 672static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
 673{
 674        struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
 675        struct hugetlbfs_inode_info *p;
 676
 677        if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
 678                return NULL;
 679        p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL);
 680        if (unlikely(!p)) {
 681                hugetlbfs_inc_free_inodes(sbinfo);
 682                return NULL;
 683        }
 684        return &p->vfs_inode;
 685}
 686
 687static void hugetlbfs_i_callback(struct rcu_head *head)
 688{
 689        struct inode *inode = container_of(head, struct inode, i_rcu);
 690        kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
 691}
 692
 693static void hugetlbfs_destroy_inode(struct inode *inode)
 694{
 695        hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
 696        mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
 697        call_rcu(&inode->i_rcu, hugetlbfs_i_callback);
 698}
 699
 700static const struct address_space_operations hugetlbfs_aops = {
 701        .write_begin    = hugetlbfs_write_begin,
 702        .write_end      = hugetlbfs_write_end,
 703        .set_page_dirty = hugetlbfs_set_page_dirty,
 704        .migratepage    = hugetlbfs_migrate_page,
 705};
 706
 707
 708static void init_once(void *foo)
 709{
 710        struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
 711
 712        inode_init_once(&ei->vfs_inode);
 713}
 714
 715const struct file_operations hugetlbfs_file_operations = {
 716        .read                   = hugetlbfs_read,
 717        .mmap                   = hugetlbfs_file_mmap,
 718        .fsync                  = noop_fsync,
 719        .get_unmapped_area      = hugetlb_get_unmapped_area,
 720        .llseek         = default_llseek,
 721};
 722
 723static const struct inode_operations hugetlbfs_dir_inode_operations = {
 724        .create         = hugetlbfs_create,
 725        .lookup         = simple_lookup,
 726        .link           = simple_link,
 727        .unlink         = simple_unlink,
 728        .symlink        = hugetlbfs_symlink,
 729        .mkdir          = hugetlbfs_mkdir,
 730        .rmdir          = simple_rmdir,
 731        .mknod          = hugetlbfs_mknod,
 732        .rename         = simple_rename,
 733        .setattr        = hugetlbfs_setattr,
 734};
 735
 736static const struct inode_operations hugetlbfs_inode_operations = {
 737        .setattr        = hugetlbfs_setattr,
 738};
 739
 740static const struct super_operations hugetlbfs_ops = {
 741        .alloc_inode    = hugetlbfs_alloc_inode,
 742        .destroy_inode  = hugetlbfs_destroy_inode,
 743        .evict_inode    = hugetlbfs_evict_inode,
 744        .statfs         = hugetlbfs_statfs,
 745        .put_super      = hugetlbfs_put_super,
 746        .show_options   = generic_show_options,
 747};
 748
 749static int
 750hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
 751{
 752        char *p, *rest;
 753        substring_t args[MAX_OPT_ARGS];
 754        int option;
 755        unsigned long long size = 0;
 756        enum { NO_SIZE, SIZE_STD, SIZE_PERCENT } setsize = NO_SIZE;
 757
 758        if (!options)
 759                return 0;
 760
 761        while ((p = strsep(&options, ",")) != NULL) {
 762                int token;
 763                if (!*p)
 764                        continue;
 765
 766                token = match_token(p, tokens, args);
 767                switch (token) {
 768                case Opt_uid:
 769                        if (match_int(&args[0], &option))
 770                                goto bad_val;
 771                        pconfig->uid = make_kuid(current_user_ns(), option);
 772                        if (!uid_valid(pconfig->uid))
 773                                goto bad_val;
 774                        break;
 775
 776                case Opt_gid:
 777                        if (match_int(&args[0], &option))
 778                                goto bad_val;
 779                        pconfig->gid = make_kgid(current_user_ns(), option);
 780                        if (!gid_valid(pconfig->gid))
 781                                goto bad_val;
 782                        break;
 783
 784                case Opt_mode:
 785                        if (match_octal(&args[0], &option))
 786                                goto bad_val;
 787                        pconfig->mode = option & 01777U;
 788                        break;
 789
 790                case Opt_size: {
 791                        /* memparse() will accept a K/M/G without a digit */
 792                        if (!isdigit(*args[0].from))
 793                                goto bad_val;
 794                        size = memparse(args[0].from, &rest);
 795                        setsize = SIZE_STD;
 796                        if (*rest == '%')
 797                                setsize = SIZE_PERCENT;
 798                        break;
 799                }
 800
 801                case Opt_nr_inodes:
 802                        /* memparse() will accept a K/M/G without a digit */
 803                        if (!isdigit(*args[0].from))
 804                                goto bad_val;
 805                        pconfig->nr_inodes = memparse(args[0].from, &rest);
 806                        break;
 807
 808                case Opt_pagesize: {
 809                        unsigned long ps;
 810                        ps = memparse(args[0].from, &rest);
 811                        pconfig->hstate = size_to_hstate(ps);
 812                        if (!pconfig->hstate) {
 813                                printk(KERN_ERR
 814                                "hugetlbfs: Unsupported page size %lu MB\n",
 815                                        ps >> 20);
 816                                return -EINVAL;
 817                        }
 818                        break;
 819                }
 820
 821                default:
 822                        printk(KERN_ERR "hugetlbfs: Bad mount option: \"%s\"\n",
 823                                 p);
 824                        return -EINVAL;
 825                        break;
 826                }
 827        }
 828
 829        /* Do size after hstate is set up */
 830        if (setsize > NO_SIZE) {
 831                struct hstate *h = pconfig->hstate;
 832                if (setsize == SIZE_PERCENT) {
 833                        size <<= huge_page_shift(h);
 834                        size *= h->max_huge_pages;
 835                        do_div(size, 100);
 836                }
 837                pconfig->nr_blocks = (size >> huge_page_shift(h));
 838        }
 839
 840        return 0;
 841
 842bad_val:
 843        printk(KERN_ERR "hugetlbfs: Bad value '%s' for mount option '%s'\n",
 844               args[0].from, p);
 845        return -EINVAL;
 846}
 847
 848static int
 849hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
 850{
 851        int ret;
 852        struct hugetlbfs_config config;
 853        struct hugetlbfs_sb_info *sbinfo;
 854
 855        save_mount_options(sb, data);
 856
 857        config.nr_blocks = -1; /* No limit on size by default */
 858        config.nr_inodes = -1; /* No limit on number of inodes by default */
 859        config.uid = current_fsuid();
 860        config.gid = current_fsgid();
 861        config.mode = 0755;
 862        config.hstate = &default_hstate;
 863        ret = hugetlbfs_parse_options(data, &config);
 864        if (ret)
 865                return ret;
 866
 867        sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
 868        if (!sbinfo)
 869                return -ENOMEM;
 870        sb->s_fs_info = sbinfo;
 871        sbinfo->hstate = config.hstate;
 872        spin_lock_init(&sbinfo->stat_lock);
 873        sbinfo->max_inodes = config.nr_inodes;
 874        sbinfo->free_inodes = config.nr_inodes;
 875        sbinfo->spool = NULL;
 876        if (config.nr_blocks != -1) {
 877                sbinfo->spool = hugepage_new_subpool(config.nr_blocks);
 878                if (!sbinfo->spool)
 879                        goto out_free;
 880        }
 881        sb->s_maxbytes = MAX_LFS_FILESIZE;
 882        sb->s_blocksize = huge_page_size(config.hstate);
 883        sb->s_blocksize_bits = huge_page_shift(config.hstate);
 884        sb->s_magic = HUGETLBFS_MAGIC;
 885        sb->s_op = &hugetlbfs_ops;
 886        sb->s_time_gran = 1;
 887        sb->s_root = d_make_root(hugetlbfs_get_root(sb, &config));
 888        if (!sb->s_root)
 889                goto out_free;
 890        return 0;
 891out_free:
 892        if (sbinfo->spool)
 893                kfree(sbinfo->spool);
 894        kfree(sbinfo);
 895        return -ENOMEM;
 896}
 897
 898static struct dentry *hugetlbfs_mount(struct file_system_type *fs_type,
 899        int flags, const char *dev_name, void *data)
 900{
 901        return mount_nodev(fs_type, flags, data, hugetlbfs_fill_super);
 902}
 903
 904static struct file_system_type hugetlbfs_fs_type = {
 905        .name           = "hugetlbfs",
 906        .mount          = hugetlbfs_mount,
 907        .kill_sb        = kill_litter_super,
 908};
 909MODULE_ALIAS_FS("hugetlbfs");
 910
 911static struct vfsmount *hugetlbfs_vfsmount[HUGE_MAX_HSTATE];
 912
 913static int can_do_hugetlb_shm(void)
 914{
 915        kgid_t shm_group;
 916        shm_group = make_kgid(&init_user_ns, sysctl_hugetlb_shm_group);
 917        return capable(CAP_IPC_LOCK) || in_group_p(shm_group);
 918}
 919
 920static int get_hstate_idx(int page_size_log)
 921{
 922        struct hstate *h = hstate_sizelog(page_size_log);
 923
 924        if (!h)
 925                return -1;
 926        return h - hstates;
 927}
 928
 929static struct dentry_operations anon_ops = {
 930        .d_dname = simple_dname
 931};
 932
 933/*
 934 * Note that size should be aligned to proper hugepage size in caller side,
 935 * otherwise hugetlb_reserve_pages reserves one less hugepages than intended.
 936 */
 937struct file *hugetlb_file_setup(const char *name, size_t size,
 938                                vm_flags_t acctflag, struct user_struct **user,
 939                                int creat_flags, int page_size_log)
 940{
 941        struct file *file = ERR_PTR(-ENOMEM);
 942        struct inode *inode;
 943        struct path path;
 944        struct super_block *sb;
 945        struct qstr quick_string;
 946        int hstate_idx;
 947
 948        hstate_idx = get_hstate_idx(page_size_log);
 949        if (hstate_idx < 0)
 950                return ERR_PTR(-ENODEV);
 951
 952        *user = NULL;
 953        if (!hugetlbfs_vfsmount[hstate_idx])
 954                return ERR_PTR(-ENOENT);
 955
 956        if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) {
 957                *user = current_user();
 958                if (user_shm_lock(size, *user)) {
 959                        task_lock(current);
 960                        printk_once(KERN_WARNING
 961                                "%s (%d): Using mlock ulimits for SHM_HUGETLB is deprecated\n",
 962                                current->comm, current->pid);
 963                        task_unlock(current);
 964                } else {
 965                        *user = NULL;
 966                        return ERR_PTR(-EPERM);
 967                }
 968        }
 969
 970        sb = hugetlbfs_vfsmount[hstate_idx]->mnt_sb;
 971        quick_string.name = name;
 972        quick_string.len = strlen(quick_string.name);
 973        quick_string.hash = 0;
 974        path.dentry = d_alloc_pseudo(sb, &quick_string);
 975        if (!path.dentry)
 976                goto out_shm_unlock;
 977
 978        d_set_d_op(path.dentry, &anon_ops);
 979        path.mnt = mntget(hugetlbfs_vfsmount[hstate_idx]);
 980        file = ERR_PTR(-ENOSPC);
 981        inode = hugetlbfs_get_inode(sb, NULL, S_IFREG | S_IRWXUGO, 0);
 982        if (!inode)
 983                goto out_dentry;
 984
 985        file = ERR_PTR(-ENOMEM);
 986        if (hugetlb_reserve_pages(inode, 0,
 987                        size >> huge_page_shift(hstate_inode(inode)), NULL,
 988                        acctflag))
 989                goto out_inode;
 990
 991        d_instantiate(path.dentry, inode);
 992        inode->i_size = size;
 993        clear_nlink(inode);
 994
 995        file = alloc_file(&path, FMODE_WRITE | FMODE_READ,
 996                        &hugetlbfs_file_operations);
 997        if (IS_ERR(file))
 998                goto out_dentry; /* inode is already attached */
 999
1000        return file;
1001
1002out_inode:
1003        iput(inode);
1004out_dentry:
1005        path_put(&path);
1006out_shm_unlock:
1007        if (*user) {
1008                user_shm_unlock(size, *user);
1009                *user = NULL;
1010        }
1011        return file;
1012}
1013
1014static int __init init_hugetlbfs_fs(void)
1015{
1016        struct hstate *h;
1017        int error;
1018        int i;
1019
1020        error = bdi_init(&hugetlbfs_backing_dev_info);
1021        if (error)
1022                return error;
1023
1024        error = -ENOMEM;
1025        hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
1026                                        sizeof(struct hugetlbfs_inode_info),
1027                                        0, 0, init_once);
1028        if (hugetlbfs_inode_cachep == NULL)
1029                goto out2;
1030
1031        error = register_filesystem(&hugetlbfs_fs_type);
1032        if (error)
1033                goto out;
1034
1035        i = 0;
1036        for_each_hstate(h) {
1037                char buf[50];
1038                unsigned ps_kb = 1U << (h->order + PAGE_SHIFT - 10);
1039
1040                snprintf(buf, sizeof(buf), "pagesize=%uK", ps_kb);
1041                hugetlbfs_vfsmount[i] = kern_mount_data(&hugetlbfs_fs_type,
1042                                                        buf);
1043
1044                if (IS_ERR(hugetlbfs_vfsmount[i])) {
1045                        pr_err("hugetlb: Cannot mount internal hugetlbfs for "
1046                                "page size %uK", ps_kb);
1047                        error = PTR_ERR(hugetlbfs_vfsmount[i]);
1048                        hugetlbfs_vfsmount[i] = NULL;
1049                }
1050                i++;
1051        }
1052        /* Non default hstates are optional */
1053        if (!IS_ERR_OR_NULL(hugetlbfs_vfsmount[default_hstate_idx]))
1054                return 0;
1055
1056 out:
1057        kmem_cache_destroy(hugetlbfs_inode_cachep);
1058 out2:
1059        bdi_destroy(&hugetlbfs_backing_dev_info);
1060        return error;
1061}
1062
1063static void __exit exit_hugetlbfs_fs(void)
1064{
1065        struct hstate *h;
1066        int i;
1067
1068
1069        /*
1070         * Make sure all delayed rcu free inodes are flushed before we
1071         * destroy cache.
1072         */
1073        rcu_barrier();
1074        kmem_cache_destroy(hugetlbfs_inode_cachep);
1075        i = 0;
1076        for_each_hstate(h)
1077                kern_unmount(hugetlbfs_vfsmount[i++]);
1078        unregister_filesystem(&hugetlbfs_fs_type);
1079        bdi_destroy(&hugetlbfs_backing_dev_info);
1080}
1081
1082module_init(init_hugetlbfs_fs)
1083module_exit(exit_hugetlbfs_fs)
1084
1085MODULE_LICENSE("GPL");
1086
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