linux/fs/hugetlbfs/inode.c
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   1/*
   2 * hugetlbpage-backed filesystem.  Based on ramfs.
   3 *
   4 * William Irwin, 2002
   5 *
   6 * Copyright (C) 2002 Linus Torvalds.
   7 */
   8
   9#include <linux/module.h>
  10#include <linux/thread_info.h>
  11#include <asm/current.h>
  12#include <linux/sched.h>                /* remove ASAP */
  13#include <linux/fs.h>
  14#include <linux/mount.h>
  15#include <linux/file.h>
  16#include <linux/kernel.h>
  17#include <linux/writeback.h>
  18#include <linux/pagemap.h>
  19#include <linux/highmem.h>
  20#include <linux/init.h>
  21#include <linux/string.h>
  22#include <linux/capability.h>
  23#include <linux/ctype.h>
  24#include <linux/backing-dev.h>
  25#include <linux/hugetlb.h>
  26#include <linux/pagevec.h>
  27#include <linux/parser.h>
  28#include <linux/mman.h>
  29#include <linux/slab.h>
  30#include <linux/dnotify.h>
  31#include <linux/statfs.h>
  32#include <linux/security.h>
  33#include <linux/magic.h>
  34#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->f_path.dentry->d_inode;
 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 | VM_DONTDUMP;
 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        unsigned long start_addr;
 155        struct hstate *h = hstate_file(file);
 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        if (len > mm->cached_hole_size)
 177                start_addr = mm->free_area_cache;
 178        else {
 179                start_addr = TASK_UNMAPPED_BASE;
 180                mm->cached_hole_size = 0;
 181        }
 182
 183full_search:
 184        addr = ALIGN(start_addr, huge_page_size(h));
 185
 186        for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
 187                /* At this point:  (!vma || addr < vma->vm_end). */
 188                if (TASK_SIZE - len < addr) {
 189                        /*
 190                         * Start a new search - just in case we missed
 191                         * some holes.
 192                         */
 193                        if (start_addr != TASK_UNMAPPED_BASE) {
 194                                start_addr = TASK_UNMAPPED_BASE;
 195                                mm->cached_hole_size = 0;
 196                                goto full_search;
 197                        }
 198                        return -ENOMEM;
 199                }
 200
 201                if (!vma || addr + len <= vma->vm_start) {
 202                        mm->free_area_cache = addr + len;
 203                        return addr;
 204                }
 205                if (addr + mm->cached_hole_size < vma->vm_start)
 206                        mm->cached_hole_size = vma->vm_start - addr;
 207                addr = ALIGN(vma->vm_end, huge_page_size(h));
 208        }
 209}
 210#endif
 211
 212static int
 213hugetlbfs_read_actor(struct page *page, unsigned long offset,
 214                        char __user *buf, unsigned long count,
 215                        unsigned long size)
 216{
 217        char *kaddr;
 218        unsigned long left, copied = 0;
 219        int i, chunksize;
 220
 221        if (size > count)
 222                size = count;
 223
 224        /* Find which 4k chunk and offset with in that chunk */
 225        i = offset >> PAGE_CACHE_SHIFT;
 226        offset = offset & ~PAGE_CACHE_MASK;
 227
 228        while (size) {
 229                chunksize = PAGE_CACHE_SIZE;
 230                if (offset)
 231                        chunksize -= offset;
 232                if (chunksize > size)
 233                        chunksize = size;
 234                kaddr = kmap(&page[i]);
 235                left = __copy_to_user(buf, kaddr + offset, chunksize);
 236                kunmap(&page[i]);
 237                if (left) {
 238                        copied += (chunksize - left);
 239                        break;
 240                }
 241                offset = 0;
 242                size -= chunksize;
 243                buf += chunksize;
 244                copied += chunksize;
 245                i++;
 246        }
 247        return copied ? copied : -EFAULT;
 248}
 249
 250/*
 251 * Support for read() - Find the page attached to f_mapping and copy out the
 252 * data. Its *very* similar to do_generic_mapping_read(), we can't use that
 253 * since it has PAGE_CACHE_SIZE assumptions.
 254 */
 255static ssize_t hugetlbfs_read(struct file *filp, char __user *buf,
 256                              size_t len, loff_t *ppos)
 257{
 258        struct hstate *h = hstate_file(filp);
 259        struct address_space *mapping = filp->f_mapping;
 260        struct inode *inode = mapping->host;
 261        unsigned long index = *ppos >> huge_page_shift(h);
 262        unsigned long offset = *ppos & ~huge_page_mask(h);
 263        unsigned long end_index;
 264        loff_t isize;
 265        ssize_t retval = 0;
 266
 267        /* validate length */
 268        if (len == 0)
 269                goto out;
 270
 271        for (;;) {
 272                struct page *page;
 273                unsigned long nr, ret;
 274                int ra;
 275
 276                /* nr is the maximum number of bytes to copy from this page */
 277                nr = huge_page_size(h);
 278                isize = i_size_read(inode);
 279                if (!isize)
 280                        goto out;
 281                end_index = (isize - 1) >> huge_page_shift(h);
 282                if (index >= end_index) {
 283                        if (index > end_index)
 284                                goto out;
 285                        nr = ((isize - 1) & ~huge_page_mask(h)) + 1;
 286                        if (nr <= offset)
 287                                goto out;
 288                }
 289                nr = nr - offset;
 290
 291                /* Find the page */
 292                page = find_lock_page(mapping, index);
 293                if (unlikely(page == NULL)) {
 294                        /*
 295                         * We have a HOLE, zero out the user-buffer for the
 296                         * length of the hole or request.
 297                         */
 298                        ret = len < nr ? len : nr;
 299                        if (clear_user(buf, ret))
 300                                ra = -EFAULT;
 301                        else
 302                                ra = 0;
 303                } else {
 304                        unlock_page(page);
 305
 306                        /*
 307                         * We have the page, copy it to user space buffer.
 308                         */
 309                        ra = hugetlbfs_read_actor(page, offset, buf, len, nr);
 310                        ret = ra;
 311                        page_cache_release(page);
 312                }
 313                if (ra < 0) {
 314                        if (retval == 0)
 315                                retval = ra;
 316                        goto out;
 317                }
 318
 319                offset += ret;
 320                retval += ret;
 321                len -= ret;
 322                index += offset >> huge_page_shift(h);
 323                offset &= ~huge_page_mask(h);
 324
 325                /* short read or no more work */
 326                if ((ret != nr) || (len == 0))
 327                        break;
 328        }
 329out:
 330        *ppos = ((loff_t)index << huge_page_shift(h)) + offset;
 331        return retval;
 332}
 333
 334static int hugetlbfs_write_begin(struct file *file,
 335                        struct address_space *mapping,
 336                        loff_t pos, unsigned len, unsigned flags,
 337                        struct page **pagep, void **fsdata)
 338{
 339        return -EINVAL;
 340}
 341
 342static int hugetlbfs_write_end(struct file *file, struct address_space *mapping,
 343                        loff_t pos, unsigned len, unsigned copied,
 344                        struct page *page, void *fsdata)
 345{
 346        BUG();
 347        return -EINVAL;
 348}
 349
 350static void truncate_huge_page(struct page *page)
 351{
 352        cancel_dirty_page(page, /* No IO accounting for huge pages? */0);
 353        ClearPageUptodate(page);
 354        delete_from_page_cache(page);
 355}
 356
 357static void truncate_hugepages(struct inode *inode, loff_t lstart)
 358{
 359        struct hstate *h = hstate_inode(inode);
 360        struct address_space *mapping = &inode->i_data;
 361        const pgoff_t start = lstart >> huge_page_shift(h);
 362        struct pagevec pvec;
 363        pgoff_t next;
 364        int i, freed = 0;
 365
 366        pagevec_init(&pvec, 0);
 367        next = start;
 368        while (1) {
 369                if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
 370                        if (next == start)
 371                                break;
 372                        next = start;
 373                        continue;
 374                }
 375
 376                for (i = 0; i < pagevec_count(&pvec); ++i) {
 377                        struct page *page = pvec.pages[i];
 378
 379                        lock_page(page);
 380                        if (page->index > next)
 381                                next = page->index;
 382                        ++next;
 383                        truncate_huge_page(page);
 384                        unlock_page(page);
 385                        freed++;
 386                }
 387                huge_pagevec_release(&pvec);
 388        }
 389        BUG_ON(!lstart && mapping->nrpages);
 390        hugetlb_unreserve_pages(inode, start, freed);
 391}
 392
 393static void hugetlbfs_evict_inode(struct inode *inode)
 394{
 395        truncate_hugepages(inode, 0);
 396        clear_inode(inode);
 397}
 398
 399static inline void
 400hugetlb_vmtruncate_list(struct rb_root *root, pgoff_t pgoff)
 401{
 402        struct vm_area_struct *vma;
 403
 404        vma_interval_tree_foreach(vma, root, pgoff, ULONG_MAX) {
 405                unsigned long v_offset;
 406
 407                /*
 408                 * Can the expression below overflow on 32-bit arches?
 409                 * No, because the interval tree returns us only those vmas
 410                 * which overlap the truncated area starting at pgoff,
 411                 * and no vma on a 32-bit arch can span beyond the 4GB.
 412                 */
 413                if (vma->vm_pgoff < pgoff)
 414                        v_offset = (pgoff - vma->vm_pgoff) << PAGE_SHIFT;
 415                else
 416                        v_offset = 0;
 417
 418                unmap_hugepage_range(vma, vma->vm_start + v_offset,
 419                                     vma->vm_end, NULL);
 420        }
 421}
 422
 423static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
 424{
 425        pgoff_t pgoff;
 426        struct address_space *mapping = inode->i_mapping;
 427        struct hstate *h = hstate_inode(inode);
 428
 429        BUG_ON(offset & ~huge_page_mask(h));
 430        pgoff = offset >> PAGE_SHIFT;
 431
 432        i_size_write(inode, offset);
 433        mutex_lock(&mapping->i_mmap_mutex);
 434        if (!RB_EMPTY_ROOT(&mapping->i_mmap))
 435                hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff);
 436        mutex_unlock(&mapping->i_mmap_mutex);
 437        truncate_hugepages(inode, offset);
 438        return 0;
 439}
 440
 441static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
 442{
 443        struct inode *inode = dentry->d_inode;
 444        struct hstate *h = hstate_inode(inode);
 445        int error;
 446        unsigned int ia_valid = attr->ia_valid;
 447
 448        BUG_ON(!inode);
 449
 450        error = inode_change_ok(inode, attr);
 451        if (error)
 452                return error;
 453
 454        if (ia_valid & ATTR_SIZE) {
 455                error = -EINVAL;
 456                if (attr->ia_size & ~huge_page_mask(h))
 457                        return -EINVAL;
 458                error = hugetlb_vmtruncate(inode, attr->ia_size);
 459                if (error)
 460                        return error;
 461        }
 462
 463        setattr_copy(inode, attr);
 464        mark_inode_dirty(inode);
 465        return 0;
 466}
 467
 468static struct inode *hugetlbfs_get_root(struct super_block *sb,
 469                                        struct hugetlbfs_config *config)
 470{
 471        struct inode *inode;
 472
 473        inode = new_inode(sb);
 474        if (inode) {
 475                struct hugetlbfs_inode_info *info;
 476                inode->i_ino = get_next_ino();
 477                inode->i_mode = S_IFDIR | config->mode;
 478                inode->i_uid = config->uid;
 479                inode->i_gid = config->gid;
 480                inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 481                info = HUGETLBFS_I(inode);
 482                mpol_shared_policy_init(&info->policy, NULL);
 483                inode->i_op = &hugetlbfs_dir_inode_operations;
 484                inode->i_fop = &simple_dir_operations;
 485                /* directory inodes start off with i_nlink == 2 (for "." entry) */
 486                inc_nlink(inode);
 487                lockdep_annotate_inode_mutex_key(inode);
 488        }
 489        return inode;
 490}
 491
 492static struct inode *hugetlbfs_get_inode(struct super_block *sb,
 493                                        struct inode *dir,
 494                                        umode_t mode, dev_t dev)
 495{
 496        struct inode *inode;
 497
 498        inode = new_inode(sb);
 499        if (inode) {
 500                struct hugetlbfs_inode_info *info;
 501                inode->i_ino = get_next_ino();
 502                inode_init_owner(inode, dir, mode);
 503                inode->i_mapping->a_ops = &hugetlbfs_aops;
 504                inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info;
 505                inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 506                INIT_LIST_HEAD(&inode->i_mapping->private_list);
 507                info = HUGETLBFS_I(inode);
 508                /*
 509                 * The policy is initialized here even if we are creating a
 510                 * private inode because initialization simply creates an
 511                 * an empty rb tree and calls spin_lock_init(), later when we
 512                 * call mpol_free_shared_policy() it will just return because
 513                 * the rb tree will still be empty.
 514                 */
 515                mpol_shared_policy_init(&info->policy, NULL);
 516                switch (mode & S_IFMT) {
 517                default:
 518                        init_special_inode(inode, mode, dev);
 519                        break;
 520                case S_IFREG:
 521                        inode->i_op = &hugetlbfs_inode_operations;
 522                        inode->i_fop = &hugetlbfs_file_operations;
 523                        break;
 524                case S_IFDIR:
 525                        inode->i_op = &hugetlbfs_dir_inode_operations;
 526                        inode->i_fop = &simple_dir_operations;
 527
 528                        /* directory inodes start off with i_nlink == 2 (for "." entry) */
 529                        inc_nlink(inode);
 530                        break;
 531                case S_IFLNK:
 532                        inode->i_op = &page_symlink_inode_operations;
 533                        break;
 534                }
 535                lockdep_annotate_inode_mutex_key(inode);
 536        }
 537        return inode;
 538}
 539
 540/*
 541 * File creation. Allocate an inode, and we're done..
 542 */
 543static int hugetlbfs_mknod(struct inode *dir,
 544                        struct dentry *dentry, umode_t mode, dev_t dev)
 545{
 546        struct inode *inode;
 547        int error = -ENOSPC;
 548
 549        inode = hugetlbfs_get_inode(dir->i_sb, dir, mode, dev);
 550        if (inode) {
 551                dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 552                d_instantiate(dentry, inode);
 553                dget(dentry);   /* Extra count - pin the dentry in core */
 554                error = 0;
 555        }
 556        return error;
 557}
 558
 559static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 560{
 561        int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
 562        if (!retval)
 563                inc_nlink(dir);
 564        return retval;
 565}
 566
 567static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl)
 568{
 569        return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
 570}
 571
 572static int hugetlbfs_symlink(struct inode *dir,
 573                        struct dentry *dentry, const char *symname)
 574{
 575        struct inode *inode;
 576        int error = -ENOSPC;
 577
 578        inode = hugetlbfs_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0);
 579        if (inode) {
 580                int l = strlen(symname)+1;
 581                error = page_symlink(inode, symname, l);
 582                if (!error) {
 583                        d_instantiate(dentry, inode);
 584                        dget(dentry);
 585                } else
 586                        iput(inode);
 587        }
 588        dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 589
 590        return error;
 591}
 592
 593/*
 594 * mark the head page dirty
 595 */
 596static int hugetlbfs_set_page_dirty(struct page *page)
 597{
 598        struct page *head = compound_head(page);
 599
 600        SetPageDirty(head);
 601        return 0;
 602}
 603
 604static int hugetlbfs_migrate_page(struct address_space *mapping,
 605                                struct page *newpage, struct page *page,
 606                                enum migrate_mode mode)
 607{
 608        int rc;
 609
 610        rc = migrate_huge_page_move_mapping(mapping, newpage, page);
 611        if (rc)
 612                return rc;
 613        migrate_page_copy(newpage, page);
 614
 615        return 0;
 616}
 617
 618static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 619{
 620        struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
 621        struct hstate *h = hstate_inode(dentry->d_inode);
 622
 623        buf->f_type = HUGETLBFS_MAGIC;
 624        buf->f_bsize = huge_page_size(h);
 625        if (sbinfo) {
 626                spin_lock(&sbinfo->stat_lock);
 627                /* If no limits set, just report 0 for max/free/used
 628                 * blocks, like simple_statfs() */
 629                if (sbinfo->spool) {
 630                        long free_pages;
 631
 632                        spin_lock(&sbinfo->spool->lock);
 633                        buf->f_blocks = sbinfo->spool->max_hpages;
 634                        free_pages = sbinfo->spool->max_hpages
 635                                - sbinfo->spool->used_hpages;
 636                        buf->f_bavail = buf->f_bfree = free_pages;
 637                        spin_unlock(&sbinfo->spool->lock);
 638                        buf->f_files = sbinfo->max_inodes;
 639                        buf->f_ffree = sbinfo->free_inodes;
 640                }
 641                spin_unlock(&sbinfo->stat_lock);
 642        }
 643        buf->f_namelen = NAME_MAX;
 644        return 0;
 645}
 646
 647static void hugetlbfs_put_super(struct super_block *sb)
 648{
 649        struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
 650
 651        if (sbi) {
 652                sb->s_fs_info = NULL;
 653
 654                if (sbi->spool)
 655                        hugepage_put_subpool(sbi->spool);
 656
 657                kfree(sbi);
 658        }
 659}
 660
 661static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
 662{
 663        if (sbinfo->free_inodes >= 0) {
 664                spin_lock(&sbinfo->stat_lock);
 665                if (unlikely(!sbinfo->free_inodes)) {
 666                        spin_unlock(&sbinfo->stat_lock);
 667                        return 0;
 668                }
 669                sbinfo->free_inodes--;
 670                spin_unlock(&sbinfo->stat_lock);
 671        }
 672
 673        return 1;
 674}
 675
 676static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
 677{
 678        if (sbinfo->free_inodes >= 0) {
 679                spin_lock(&sbinfo->stat_lock);
 680                sbinfo->free_inodes++;
 681                spin_unlock(&sbinfo->stat_lock);
 682        }
 683}
 684
 685
 686static struct kmem_cache *hugetlbfs_inode_cachep;
 687
 688static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
 689{
 690        struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
 691        struct hugetlbfs_inode_info *p;
 692
 693        if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
 694                return NULL;
 695        p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL);
 696        if (unlikely(!p)) {
 697                hugetlbfs_inc_free_inodes(sbinfo);
 698                return NULL;
 699        }
 700        return &p->vfs_inode;
 701}
 702
 703static void hugetlbfs_i_callback(struct rcu_head *head)
 704{
 705        struct inode *inode = container_of(head, struct inode, i_rcu);
 706        kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
 707}
 708
 709static void hugetlbfs_destroy_inode(struct inode *inode)
 710{
 711        hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
 712        mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
 713        call_rcu(&inode->i_rcu, hugetlbfs_i_callback);
 714}
 715
 716static const struct address_space_operations hugetlbfs_aops = {
 717        .write_begin    = hugetlbfs_write_begin,
 718        .write_end      = hugetlbfs_write_end,
 719        .set_page_dirty = hugetlbfs_set_page_dirty,
 720        .migratepage    = hugetlbfs_migrate_page,
 721};
 722
 723
 724static void init_once(void *foo)
 725{
 726        struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
 727
 728        inode_init_once(&ei->vfs_inode);
 729}
 730
 731const struct file_operations hugetlbfs_file_operations = {
 732        .read                   = hugetlbfs_read,
 733        .mmap                   = hugetlbfs_file_mmap,
 734        .fsync                  = noop_fsync,
 735        .get_unmapped_area      = hugetlb_get_unmapped_area,
 736        .llseek         = default_llseek,
 737};
 738
 739static const struct inode_operations hugetlbfs_dir_inode_operations = {
 740        .create         = hugetlbfs_create,
 741        .lookup         = simple_lookup,
 742        .link           = simple_link,
 743        .unlink         = simple_unlink,
 744        .symlink        = hugetlbfs_symlink,
 745        .mkdir          = hugetlbfs_mkdir,
 746        .rmdir          = simple_rmdir,
 747        .mknod          = hugetlbfs_mknod,
 748        .rename         = simple_rename,
 749        .setattr        = hugetlbfs_setattr,
 750};
 751
 752static const struct inode_operations hugetlbfs_inode_operations = {
 753        .setattr        = hugetlbfs_setattr,
 754};
 755
 756static const struct super_operations hugetlbfs_ops = {
 757        .alloc_inode    = hugetlbfs_alloc_inode,
 758        .destroy_inode  = hugetlbfs_destroy_inode,
 759        .evict_inode    = hugetlbfs_evict_inode,
 760        .statfs         = hugetlbfs_statfs,
 761        .put_super      = hugetlbfs_put_super,
 762        .show_options   = generic_show_options,
 763};
 764
 765static int
 766hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
 767{
 768        char *p, *rest;
 769        substring_t args[MAX_OPT_ARGS];
 770        int option;
 771        unsigned long long size = 0;
 772        enum { NO_SIZE, SIZE_STD, SIZE_PERCENT } setsize = NO_SIZE;
 773
 774        if (!options)
 775                return 0;
 776
 777        while ((p = strsep(&options, ",")) != NULL) {
 778                int token;
 779                if (!*p)
 780                        continue;
 781
 782                token = match_token(p, tokens, args);
 783                switch (token) {
 784                case Opt_uid:
 785                        if (match_int(&args[0], &option))
 786                                goto bad_val;
 787                        pconfig->uid = make_kuid(current_user_ns(), option);
 788                        if (!uid_valid(pconfig->uid))
 789                                goto bad_val;
 790                        break;
 791
 792                case Opt_gid:
 793                        if (match_int(&args[0], &option))
 794                                goto bad_val;
 795                        pconfig->gid = make_kgid(current_user_ns(), option);
 796                        if (!gid_valid(pconfig->gid))
 797                                goto bad_val;
 798                        break;
 799
 800                case Opt_mode:
 801                        if (match_octal(&args[0], &option))
 802                                goto bad_val;
 803                        pconfig->mode = option & 01777U;
 804                        break;
 805
 806                case Opt_size: {
 807                        /* memparse() will accept a K/M/G without a digit */
 808                        if (!isdigit(*args[0].from))
 809                                goto bad_val;
 810                        size = memparse(args[0].from, &rest);
 811                        setsize = SIZE_STD;
 812                        if (*rest == '%')
 813                                setsize = SIZE_PERCENT;
 814                        break;
 815                }
 816
 817                case Opt_nr_inodes:
 818                        /* memparse() will accept a K/M/G without a digit */
 819                        if (!isdigit(*args[0].from))
 820                                goto bad_val;
 821                        pconfig->nr_inodes = memparse(args[0].from, &rest);
 822                        break;
 823
 824                case Opt_pagesize: {
 825                        unsigned long ps;
 826                        ps = memparse(args[0].from, &rest);
 827                        pconfig->hstate = size_to_hstate(ps);
 828                        if (!pconfig->hstate) {
 829                                printk(KERN_ERR
 830                                "hugetlbfs: Unsupported page size %lu MB\n",
 831                                        ps >> 20);
 832                                return -EINVAL;
 833                        }
 834                        break;
 835                }
 836
 837                default:
 838                        printk(KERN_ERR "hugetlbfs: Bad mount option: \"%s\"\n",
 839                                 p);
 840                        return -EINVAL;
 841                        break;
 842                }
 843        }
 844
 845        /* Do size after hstate is set up */
 846        if (setsize > NO_SIZE) {
 847                struct hstate *h = pconfig->hstate;
 848                if (setsize == SIZE_PERCENT) {
 849                        size <<= huge_page_shift(h);
 850                        size *= h->max_huge_pages;
 851                        do_div(size, 100);
 852                }
 853                pconfig->nr_blocks = (size >> huge_page_shift(h));
 854        }
 855
 856        return 0;
 857
 858bad_val:
 859        printk(KERN_ERR "hugetlbfs: Bad value '%s' for mount option '%s'\n",
 860               args[0].from, p);
 861        return -EINVAL;
 862}
 863
 864static int
 865hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
 866{
 867        int ret;
 868        struct hugetlbfs_config config;
 869        struct hugetlbfs_sb_info *sbinfo;
 870
 871        save_mount_options(sb, data);
 872
 873        config.nr_blocks = -1; /* No limit on size by default */
 874        config.nr_inodes = -1; /* No limit on number of inodes by default */
 875        config.uid = current_fsuid();
 876        config.gid = current_fsgid();
 877        config.mode = 0755;
 878        config.hstate = &default_hstate;
 879        ret = hugetlbfs_parse_options(data, &config);
 880        if (ret)
 881                return ret;
 882
 883        sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
 884        if (!sbinfo)
 885                return -ENOMEM;
 886        sb->s_fs_info = sbinfo;
 887        sbinfo->hstate = config.hstate;
 888        spin_lock_init(&sbinfo->stat_lock);
 889        sbinfo->max_inodes = config.nr_inodes;
 890        sbinfo->free_inodes = config.nr_inodes;
 891        sbinfo->spool = NULL;
 892        if (config.nr_blocks != -1) {
 893                sbinfo->spool = hugepage_new_subpool(config.nr_blocks);
 894                if (!sbinfo->spool)
 895                        goto out_free;
 896        }
 897        sb->s_maxbytes = MAX_LFS_FILESIZE;
 898        sb->s_blocksize = huge_page_size(config.hstate);
 899        sb->s_blocksize_bits = huge_page_shift(config.hstate);
 900        sb->s_magic = HUGETLBFS_MAGIC;
 901        sb->s_op = &hugetlbfs_ops;
 902        sb->s_time_gran = 1;
 903        sb->s_root = d_make_root(hugetlbfs_get_root(sb, &config));
 904        if (!sb->s_root)
 905                goto out_free;
 906        return 0;
 907out_free:
 908        if (sbinfo->spool)
 909                kfree(sbinfo->spool);
 910        kfree(sbinfo);
 911        return -ENOMEM;
 912}
 913
 914static struct dentry *hugetlbfs_mount(struct file_system_type *fs_type,
 915        int flags, const char *dev_name, void *data)
 916{
 917        return mount_nodev(fs_type, flags, data, hugetlbfs_fill_super);
 918}
 919
 920static struct file_system_type hugetlbfs_fs_type = {
 921        .name           = "hugetlbfs",
 922        .mount          = hugetlbfs_mount,
 923        .kill_sb        = kill_litter_super,
 924};
 925
 926static struct vfsmount *hugetlbfs_vfsmount;
 927
 928static int can_do_hugetlb_shm(void)
 929{
 930        kgid_t shm_group;
 931        shm_group = make_kgid(&init_user_ns, sysctl_hugetlb_shm_group);
 932        return capable(CAP_IPC_LOCK) || in_group_p(shm_group);
 933}
 934
 935struct file *hugetlb_file_setup(const char *name, unsigned long addr,
 936                                size_t size, vm_flags_t acctflag,
 937                                struct user_struct **user, int creat_flags)
 938{
 939        int error = -ENOMEM;
 940        struct file *file;
 941        struct inode *inode;
 942        struct path path;
 943        struct dentry *root;
 944        struct qstr quick_string;
 945        struct hstate *hstate;
 946        unsigned long num_pages;
 947
 948        *user = NULL;
 949        if (!hugetlbfs_vfsmount)
 950                return ERR_PTR(-ENOENT);
 951
 952        if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) {
 953                *user = current_user();
 954                if (user_shm_lock(size, *user)) {
 955                        task_lock(current);
 956                        printk_once(KERN_WARNING
 957                                "%s (%d): Using mlock ulimits for SHM_HUGETLB is deprecated\n",
 958                                current->comm, current->pid);
 959                        task_unlock(current);
 960                } else {
 961                        *user = NULL;
 962                        return ERR_PTR(-EPERM);
 963                }
 964        }
 965
 966        root = hugetlbfs_vfsmount->mnt_root;
 967        quick_string.name = name;
 968        quick_string.len = strlen(quick_string.name);
 969        quick_string.hash = 0;
 970        path.dentry = d_alloc(root, &quick_string);
 971        if (!path.dentry)
 972                goto out_shm_unlock;
 973
 974        path.mnt = mntget(hugetlbfs_vfsmount);
 975        error = -ENOSPC;
 976        inode = hugetlbfs_get_inode(root->d_sb, NULL, S_IFREG | S_IRWXUGO, 0);
 977        if (!inode)
 978                goto out_dentry;
 979
 980        hstate = hstate_inode(inode);
 981        size += addr & ~huge_page_mask(hstate);
 982        num_pages = ALIGN(size, huge_page_size(hstate)) >>
 983                        huge_page_shift(hstate);
 984        error = -ENOMEM;
 985        if (hugetlb_reserve_pages(inode, 0, num_pages, NULL, acctflag))
 986                goto out_inode;
 987
 988        d_instantiate(path.dentry, inode);
 989        inode->i_size = size;
 990        clear_nlink(inode);
 991
 992        error = -ENFILE;
 993        file = alloc_file(&path, FMODE_WRITE | FMODE_READ,
 994                        &hugetlbfs_file_operations);
 995        if (!file)
 996                goto out_dentry; /* inode is already attached */
 997
 998        return file;
 999
1000out_inode:
1001        iput(inode);
1002out_dentry:
1003        path_put(&path);
1004out_shm_unlock:
1005        if (*user) {
1006                user_shm_unlock(size, *user);
1007                *user = NULL;
1008        }
1009        return ERR_PTR(error);
1010}
1011
1012static int __init init_hugetlbfs_fs(void)
1013{
1014        int error;
1015        struct vfsmount *vfsmount;
1016
1017        error = bdi_init(&hugetlbfs_backing_dev_info);
1018        if (error)
1019                return error;
1020
1021        error = -ENOMEM;
1022        hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
1023                                        sizeof(struct hugetlbfs_inode_info),
1024                                        0, 0, init_once);
1025        if (hugetlbfs_inode_cachep == NULL)
1026                goto out2;
1027
1028        error = register_filesystem(&hugetlbfs_fs_type);
1029        if (error)
1030                goto out;
1031
1032        vfsmount = kern_mount(&hugetlbfs_fs_type);
1033
1034        if (!IS_ERR(vfsmount)) {
1035                hugetlbfs_vfsmount = vfsmount;
1036                return 0;
1037        }
1038
1039        error = PTR_ERR(vfsmount);
1040
1041 out:
1042        kmem_cache_destroy(hugetlbfs_inode_cachep);
1043 out2:
1044        bdi_destroy(&hugetlbfs_backing_dev_info);
1045        return error;
1046}
1047
1048static void __exit exit_hugetlbfs_fs(void)
1049{
1050        /*
1051         * Make sure all delayed rcu free inodes are flushed before we
1052         * destroy cache.
1053         */
1054        rcu_barrier();
1055        kmem_cache_destroy(hugetlbfs_inode_cachep);
1056        kern_unmount(hugetlbfs_vfsmount);
1057        unregister_filesystem(&hugetlbfs_fs_type);
1058        bdi_destroy(&hugetlbfs_backing_dev_info);
1059}
1060
1061module_init(init_hugetlbfs_fs)
1062module_exit(exit_hugetlbfs_fs)
1063
1064MODULE_LICENSE("GPL");
1065
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