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/quotaops.h>
  30#include <linux/slab.h>
  31#include <linux/dnotify.h>
  32#include <linux/statfs.h>
  33#include <linux/security.h>
  34
  35#include <asm/uaccess.h>
  36
  37/* some random number */
  38#define HUGETLBFS_MAGIC 0x958458f6
  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
  46static struct backing_dev_info hugetlbfs_backing_dev_info = {
  47        .ra_pages       = 0,    /* No readahead */
  48        .capabilities   = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
  49};
  50
  51int sysctl_hugetlb_shm_group;
  52
  53enum {
  54        Opt_size, Opt_nr_inodes,
  55        Opt_mode, Opt_uid, Opt_gid,
  56        Opt_err,
  57};
  58
  59static match_table_t tokens = {
  60        {Opt_size,      "size=%s"},
  61        {Opt_nr_inodes, "nr_inodes=%s"},
  62        {Opt_mode,      "mode=%o"},
  63        {Opt_uid,       "uid=%u"},
  64        {Opt_gid,       "gid=%u"},
  65        {Opt_err,       NULL},
  66};
  67
  68static void huge_pagevec_release(struct pagevec *pvec)
  69{
  70        int i;
  71
  72        for (i = 0; i < pagevec_count(pvec); ++i)
  73                put_page(pvec->pages[i]);
  74
  75        pagevec_reinit(pvec);
  76}
  77
  78static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
  79{
  80        struct inode *inode = file->f_path.dentry->d_inode;
  81        loff_t len, vma_len;
  82        int ret;
  83
  84        /*
  85         * vma address alignment (but not the pgoff alignment) has
  86         * already been checked by prepare_hugepage_range.  If you add
  87         * any error returns here, do so after setting VM_HUGETLB, so
  88         * is_vm_hugetlb_page tests below unmap_region go the right
  89         * way when do_mmap_pgoff unwinds (may be important on powerpc
  90         * and ia64).
  91         */
  92        vma->vm_flags |= VM_HUGETLB | VM_RESERVED;
  93        vma->vm_ops = &hugetlb_vm_ops;
  94
  95        if (vma->vm_pgoff & ~(HPAGE_MASK >> PAGE_SHIFT))
  96                return -EINVAL;
  97
  98        vma_len = (loff_t)(vma->vm_end - vma->vm_start);
  99
 100        mutex_lock(&inode->i_mutex);
 101        file_accessed(file);
 102
 103        ret = -ENOMEM;
 104        len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
 105
 106        if (vma->vm_flags & VM_MAYSHARE &&
 107            hugetlb_reserve_pages(inode, vma->vm_pgoff >> (HPAGE_SHIFT-PAGE_SHIFT),
 108                                  len >> HPAGE_SHIFT))
 109                goto out;
 110
 111        ret = 0;
 112        hugetlb_prefault_arch_hook(vma->vm_mm);
 113        if (vma->vm_flags & VM_WRITE && inode->i_size < len)
 114                inode->i_size = len;
 115out:
 116        mutex_unlock(&inode->i_mutex);
 117
 118        return ret;
 119}
 120
 121/*
 122 * Called under down_write(mmap_sem).
 123 */
 124
 125#ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
 126static unsigned long
 127hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 128                unsigned long len, unsigned long pgoff, unsigned long flags)
 129{
 130        struct mm_struct *mm = current->mm;
 131        struct vm_area_struct *vma;
 132        unsigned long start_addr;
 133
 134        if (len & ~HPAGE_MASK)
 135                return -EINVAL;
 136        if (len > TASK_SIZE)
 137                return -ENOMEM;
 138
 139        if (flags & MAP_FIXED) {
 140                if (prepare_hugepage_range(addr, len))
 141                        return -EINVAL;
 142                return addr;
 143        }
 144
 145        if (addr) {
 146                addr = ALIGN(addr, HPAGE_SIZE);
 147                vma = find_vma(mm, addr);
 148                if (TASK_SIZE - len >= addr &&
 149                    (!vma || addr + len <= vma->vm_start))
 150                        return addr;
 151        }
 152
 153        start_addr = mm->free_area_cache;
 154
 155        if (len <= mm->cached_hole_size)
 156                start_addr = TASK_UNMAPPED_BASE;
 157
 158full_search:
 159        addr = ALIGN(start_addr, HPAGE_SIZE);
 160
 161        for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
 162                /* At this point:  (!vma || addr < vma->vm_end). */
 163                if (TASK_SIZE - len < addr) {
 164                        /*
 165                         * Start a new search - just in case we missed
 166                         * some holes.
 167                         */
 168                        if (start_addr != TASK_UNMAPPED_BASE) {
 169                                start_addr = TASK_UNMAPPED_BASE;
 170                                goto full_search;
 171                        }
 172                        return -ENOMEM;
 173                }
 174
 175                if (!vma || addr + len <= vma->vm_start)
 176                        return addr;
 177                addr = ALIGN(vma->vm_end, HPAGE_SIZE);
 178        }
 179}
 180#endif
 181
 182static int
 183hugetlbfs_read_actor(struct page *page, unsigned long offset,
 184                        char __user *buf, unsigned long count,
 185                        unsigned long size)
 186{
 187        char *kaddr;
 188        unsigned long left, copied = 0;
 189        int i, chunksize;
 190
 191        if (size > count)
 192                size = count;
 193
 194        /* Find which 4k chunk and offset with in that chunk */
 195        i = offset >> PAGE_CACHE_SHIFT;
 196        offset = offset & ~PAGE_CACHE_MASK;
 197
 198        while (size) {
 199                chunksize = PAGE_CACHE_SIZE;
 200                if (offset)
 201                        chunksize -= offset;
 202                if (chunksize > size)
 203                        chunksize = size;
 204                kaddr = kmap(&page[i]);
 205                left = __copy_to_user(buf, kaddr + offset, chunksize);
 206                kunmap(&page[i]);
 207                if (left) {
 208                        copied += (chunksize - left);
 209                        break;
 210                }
 211                offset = 0;
 212                size -= chunksize;
 213                buf += chunksize;
 214                copied += chunksize;
 215                i++;
 216        }
 217        return copied ? copied : -EFAULT;
 218}
 219
 220/*
 221 * Support for read() - Find the page attached to f_mapping and copy out the
 222 * data. Its *very* similar to do_generic_mapping_read(), we can't use that
 223 * since it has PAGE_CACHE_SIZE assumptions.
 224 */
 225static ssize_t hugetlbfs_read(struct file *filp, char __user *buf,
 226                              size_t len, loff_t *ppos)
 227{
 228        struct address_space *mapping = filp->f_mapping;
 229        struct inode *inode = mapping->host;
 230        unsigned long index = *ppos >> HPAGE_SHIFT;
 231        unsigned long offset = *ppos & ~HPAGE_MASK;
 232        unsigned long end_index;
 233        loff_t isize;
 234        ssize_t retval = 0;
 235
 236        mutex_lock(&inode->i_mutex);
 237
 238        /* validate length */
 239        if (len == 0)
 240                goto out;
 241
 242        isize = i_size_read(inode);
 243        if (!isize)
 244                goto out;
 245
 246        end_index = (isize - 1) >> HPAGE_SHIFT;
 247        for (;;) {
 248                struct page *page;
 249                int nr, ret;
 250
 251                /* nr is the maximum number of bytes to copy from this page */
 252                nr = HPAGE_SIZE;
 253                if (index >= end_index) {
 254                        if (index > end_index)
 255                                goto out;
 256                        nr = ((isize - 1) & ~HPAGE_MASK) + 1;
 257                        if (nr <= offset) {
 258                                goto out;
 259                        }
 260                }
 261                nr = nr - offset;
 262
 263                /* Find the page */
 264                page = find_get_page(mapping, index);
 265                if (unlikely(page == NULL)) {
 266                        /*
 267                         * We have a HOLE, zero out the user-buffer for the
 268                         * length of the hole or request.
 269                         */
 270                        ret = len < nr ? len : nr;
 271                        if (clear_user(buf, ret))
 272                                ret = -EFAULT;
 273                } else {
 274                        /*
 275                         * We have the page, copy it to user space buffer.
 276                         */
 277                        ret = hugetlbfs_read_actor(page, offset, buf, len, nr);
 278                }
 279                if (ret < 0) {
 280                        if (retval == 0)
 281                                retval = ret;
 282                        if (page)
 283                                page_cache_release(page);
 284                        goto out;
 285                }
 286
 287                offset += ret;
 288                retval += ret;
 289                len -= ret;
 290                index += offset >> HPAGE_SHIFT;
 291                offset &= ~HPAGE_MASK;
 292
 293                if (page)
 294                        page_cache_release(page);
 295
 296                /* short read or no more work */
 297                if ((ret != nr) || (len == 0))
 298                        break;
 299        }
 300out:
 301        *ppos = ((loff_t)index << HPAGE_SHIFT) + offset;
 302        mutex_unlock(&inode->i_mutex);
 303        return retval;
 304}
 305
 306/*
 307 * Read a page. Again trivial. If it didn't already exist
 308 * in the page cache, it is zero-filled.
 309 */
 310static int hugetlbfs_readpage(struct file *file, struct page * page)
 311{
 312        unlock_page(page);
 313        return -EINVAL;
 314}
 315
 316static int hugetlbfs_write_begin(struct file *file,
 317                        struct address_space *mapping,
 318                        loff_t pos, unsigned len, unsigned flags,
 319                        struct page **pagep, void **fsdata)
 320{
 321        return -EINVAL;
 322}
 323
 324static int hugetlbfs_write_end(struct file *file, struct address_space *mapping,
 325                        loff_t pos, unsigned len, unsigned copied,
 326                        struct page *page, void *fsdata)
 327{
 328        BUG();
 329        return -EINVAL;
 330}
 331
 332static void truncate_huge_page(struct page *page)
 333{
 334        cancel_dirty_page(page, /* No IO accounting for huge pages? */0);
 335        ClearPageUptodate(page);
 336        remove_from_page_cache(page);
 337        put_page(page);
 338}
 339
 340static void truncate_hugepages(struct inode *inode, loff_t lstart)
 341{
 342        struct address_space *mapping = &inode->i_data;
 343        const pgoff_t start = lstart >> HPAGE_SHIFT;
 344        struct pagevec pvec;
 345        pgoff_t next;
 346        int i, freed = 0;
 347
 348        pagevec_init(&pvec, 0);
 349        next = start;
 350        while (1) {
 351                if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
 352                        if (next == start)
 353                                break;
 354                        next = start;
 355                        continue;
 356                }
 357
 358                for (i = 0; i < pagevec_count(&pvec); ++i) {
 359                        struct page *page = pvec.pages[i];
 360
 361                        lock_page(page);
 362                        if (page->index > next)
 363                                next = page->index;
 364                        ++next;
 365                        truncate_huge_page(page);
 366                        unlock_page(page);
 367                        freed++;
 368                }
 369                huge_pagevec_release(&pvec);
 370        }
 371        BUG_ON(!lstart && mapping->nrpages);
 372        hugetlb_unreserve_pages(inode, start, freed);
 373}
 374
 375static void hugetlbfs_delete_inode(struct inode *inode)
 376{
 377        truncate_hugepages(inode, 0);
 378        clear_inode(inode);
 379}
 380
 381static void hugetlbfs_forget_inode(struct inode *inode) __releases(inode_lock)
 382{
 383        struct super_block *sb = inode->i_sb;
 384
 385        if (!hlist_unhashed(&inode->i_hash)) {
 386                if (!(inode->i_state & (I_DIRTY|I_SYNC)))
 387                        list_move(&inode->i_list, &inode_unused);
 388                inodes_stat.nr_unused++;
 389                if (!sb || (sb->s_flags & MS_ACTIVE)) {
 390                        spin_unlock(&inode_lock);
 391                        return;
 392                }
 393                inode->i_state |= I_WILL_FREE;
 394                spin_unlock(&inode_lock);
 395                /*
 396                 * write_inode_now is a noop as we set BDI_CAP_NO_WRITEBACK
 397                 * in our backing_dev_info.
 398                 */
 399                write_inode_now(inode, 1);
 400                spin_lock(&inode_lock);
 401                inode->i_state &= ~I_WILL_FREE;
 402                inodes_stat.nr_unused--;
 403                hlist_del_init(&inode->i_hash);
 404        }
 405        list_del_init(&inode->i_list);
 406        list_del_init(&inode->i_sb_list);
 407        inode->i_state |= I_FREEING;
 408        inodes_stat.nr_inodes--;
 409        spin_unlock(&inode_lock);
 410        truncate_hugepages(inode, 0);
 411        clear_inode(inode);
 412        destroy_inode(inode);
 413}
 414
 415static void hugetlbfs_drop_inode(struct inode *inode)
 416{
 417        if (!inode->i_nlink)
 418                generic_delete_inode(inode);
 419        else
 420                hugetlbfs_forget_inode(inode);
 421}
 422
 423static inline void
 424hugetlb_vmtruncate_list(struct prio_tree_root *root, pgoff_t pgoff)
 425{
 426        struct vm_area_struct *vma;
 427        struct prio_tree_iter iter;
 428
 429        vma_prio_tree_foreach(vma, &iter, root, pgoff, ULONG_MAX) {
 430                unsigned long v_offset;
 431
 432                /*
 433                 * Can the expression below overflow on 32-bit arches?
 434                 * No, because the prio_tree returns us only those vmas
 435                 * which overlap the truncated area starting at pgoff,
 436                 * and no vma on a 32-bit arch can span beyond the 4GB.
 437                 */
 438                if (vma->vm_pgoff < pgoff)
 439                        v_offset = (pgoff - vma->vm_pgoff) << PAGE_SHIFT;
 440                else
 441                        v_offset = 0;
 442
 443                __unmap_hugepage_range(vma,
 444                                vma->vm_start + v_offset, vma->vm_end);
 445        }
 446}
 447
 448static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
 449{
 450        pgoff_t pgoff;
 451        struct address_space *mapping = inode->i_mapping;
 452
 453        BUG_ON(offset & ~HPAGE_MASK);
 454        pgoff = offset >> PAGE_SHIFT;
 455
 456        i_size_write(inode, offset);
 457        spin_lock(&mapping->i_mmap_lock);
 458        if (!prio_tree_empty(&mapping->i_mmap))
 459                hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff);
 460        spin_unlock(&mapping->i_mmap_lock);
 461        truncate_hugepages(inode, offset);
 462        return 0;
 463}
 464
 465static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
 466{
 467        struct inode *inode = dentry->d_inode;
 468        int error;
 469        unsigned int ia_valid = attr->ia_valid;
 470
 471        BUG_ON(!inode);
 472
 473        error = inode_change_ok(inode, attr);
 474        if (error)
 475                goto out;
 476
 477        if (ia_valid & ATTR_SIZE) {
 478                error = -EINVAL;
 479                if (!(attr->ia_size & ~HPAGE_MASK))
 480                        error = hugetlb_vmtruncate(inode, attr->ia_size);
 481                if (error)
 482                        goto out;
 483                attr->ia_valid &= ~ATTR_SIZE;
 484        }
 485        error = inode_setattr(inode, attr);
 486out:
 487        return error;
 488}
 489
 490static struct inode *hugetlbfs_get_inode(struct super_block *sb, uid_t uid, 
 491                                        gid_t gid, int mode, dev_t dev)
 492{
 493        struct inode *inode;
 494
 495        inode = new_inode(sb);
 496        if (inode) {
 497                struct hugetlbfs_inode_info *info;
 498                inode->i_mode = mode;
 499                inode->i_uid = uid;
 500                inode->i_gid = gid;
 501                inode->i_blocks = 0;
 502                inode->i_mapping->a_ops = &hugetlbfs_aops;
 503                inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info;
 504                inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 505                INIT_LIST_HEAD(&inode->i_mapping->private_list);
 506                info = HUGETLBFS_I(inode);
 507                mpol_shared_policy_init(&info->policy, MPOL_DEFAULT, NULL);
 508                switch (mode & S_IFMT) {
 509                default:
 510                        init_special_inode(inode, mode, dev);
 511                        break;
 512                case S_IFREG:
 513                        inode->i_op = &hugetlbfs_inode_operations;
 514                        inode->i_fop = &hugetlbfs_file_operations;
 515                        break;
 516                case S_IFDIR:
 517                        inode->i_op = &hugetlbfs_dir_inode_operations;
 518                        inode->i_fop = &simple_dir_operations;
 519
 520                        /* directory inodes start off with i_nlink == 2 (for "." entry) */
 521                        inc_nlink(inode);
 522                        break;
 523                case S_IFLNK:
 524                        inode->i_op = &page_symlink_inode_operations;
 525                        break;
 526                }
 527        }
 528        return inode;
 529}
 530
 531/*
 532 * File creation. Allocate an inode, and we're done..
 533 */
 534static int hugetlbfs_mknod(struct inode *dir,
 535                        struct dentry *dentry, int mode, dev_t dev)
 536{
 537        struct inode *inode;
 538        int error = -ENOSPC;
 539        gid_t gid;
 540
 541        if (dir->i_mode & S_ISGID) {
 542                gid = dir->i_gid;
 543                if (S_ISDIR(mode))
 544                        mode |= S_ISGID;
 545        } else {
 546                gid = current->fsgid;
 547        }
 548        inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid, gid, 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, int 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, int mode, struct nameidata *nd)
 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        gid_t gid;
 577
 578        if (dir->i_mode & S_ISGID)
 579                gid = dir->i_gid;
 580        else
 581                gid = current->fsgid;
 582
 583        inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid,
 584                                        gid, S_IFLNK|S_IRWXUGO, 0);
 585        if (inode) {
 586                int l = strlen(symname)+1;
 587                error = page_symlink(inode, symname, l);
 588                if (!error) {
 589                        d_instantiate(dentry, inode);
 590                        dget(dentry);
 591                } else
 592                        iput(inode);
 593        }
 594        dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 595
 596        return error;
 597}
 598
 599/*
 600 * mark the head page dirty
 601 */
 602static int hugetlbfs_set_page_dirty(struct page *page)
 603{
 604        struct page *head = compound_head(page);
 605
 606        SetPageDirty(head);
 607        return 0;
 608}
 609
 610static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 611{
 612        struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
 613
 614        buf->f_type = HUGETLBFS_MAGIC;
 615        buf->f_bsize = HPAGE_SIZE;
 616        if (sbinfo) {
 617                spin_lock(&sbinfo->stat_lock);
 618                /* If no limits set, just report 0 for max/free/used
 619                 * blocks, like simple_statfs() */
 620                if (sbinfo->max_blocks >= 0) {
 621                        buf->f_blocks = sbinfo->max_blocks;
 622                        buf->f_bavail = buf->f_bfree = sbinfo->free_blocks;
 623                        buf->f_files = sbinfo->max_inodes;
 624                        buf->f_ffree = sbinfo->free_inodes;
 625                }
 626                spin_unlock(&sbinfo->stat_lock);
 627        }
 628        buf->f_namelen = NAME_MAX;
 629        return 0;
 630}
 631
 632static void hugetlbfs_put_super(struct super_block *sb)
 633{
 634        struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
 635
 636        if (sbi) {
 637                sb->s_fs_info = NULL;
 638                kfree(sbi);
 639        }
 640}
 641
 642static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
 643{
 644        if (sbinfo->free_inodes >= 0) {
 645                spin_lock(&sbinfo->stat_lock);
 646                if (unlikely(!sbinfo->free_inodes)) {
 647                        spin_unlock(&sbinfo->stat_lock);
 648                        return 0;
 649                }
 650                sbinfo->free_inodes--;
 651                spin_unlock(&sbinfo->stat_lock);
 652        }
 653
 654        return 1;
 655}
 656
 657static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
 658{
 659        if (sbinfo->free_inodes >= 0) {
 660                spin_lock(&sbinfo->stat_lock);
 661                sbinfo->free_inodes++;
 662                spin_unlock(&sbinfo->stat_lock);
 663        }
 664}
 665
 666
 667static struct kmem_cache *hugetlbfs_inode_cachep;
 668
 669static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
 670{
 671        struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
 672        struct hugetlbfs_inode_info *p;
 673
 674        if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
 675                return NULL;
 676        p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL);
 677        if (unlikely(!p)) {
 678                hugetlbfs_inc_free_inodes(sbinfo);
 679                return NULL;
 680        }
 681        return &p->vfs_inode;
 682}
 683
 684static void hugetlbfs_destroy_inode(struct inode *inode)
 685{
 686        hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
 687        mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
 688        kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
 689}
 690
 691static const struct address_space_operations hugetlbfs_aops = {
 692        .readpage       = hugetlbfs_readpage,
 693        .write_begin    = hugetlbfs_write_begin,
 694        .write_end      = hugetlbfs_write_end,
 695        .set_page_dirty = hugetlbfs_set_page_dirty,
 696};
 697
 698
 699static void init_once(struct kmem_cache *cachep, void *foo)
 700{
 701        struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
 702
 703        inode_init_once(&ei->vfs_inode);
 704}
 705
 706const struct file_operations hugetlbfs_file_operations = {
 707        .read                   = hugetlbfs_read,
 708        .mmap                   = hugetlbfs_file_mmap,
 709        .fsync                  = simple_sync_file,
 710        .get_unmapped_area      = hugetlb_get_unmapped_area,
 711};
 712
 713static const struct inode_operations hugetlbfs_dir_inode_operations = {
 714        .create         = hugetlbfs_create,
 715        .lookup         = simple_lookup,
 716        .link           = simple_link,
 717        .unlink         = simple_unlink,
 718        .symlink        = hugetlbfs_symlink,
 719        .mkdir          = hugetlbfs_mkdir,
 720        .rmdir          = simple_rmdir,
 721        .mknod          = hugetlbfs_mknod,
 722        .rename         = simple_rename,
 723        .setattr        = hugetlbfs_setattr,
 724};
 725
 726static const struct inode_operations hugetlbfs_inode_operations = {
 727        .setattr        = hugetlbfs_setattr,
 728};
 729
 730static const struct super_operations hugetlbfs_ops = {
 731        .alloc_inode    = hugetlbfs_alloc_inode,
 732        .destroy_inode  = hugetlbfs_destroy_inode,
 733        .statfs         = hugetlbfs_statfs,
 734        .delete_inode   = hugetlbfs_delete_inode,
 735        .drop_inode     = hugetlbfs_drop_inode,
 736        .put_super      = hugetlbfs_put_super,
 737};
 738
 739static int
 740hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
 741{
 742        char *p, *rest;
 743        substring_t args[MAX_OPT_ARGS];
 744        int option;
 745
 746        if (!options)
 747                return 0;
 748
 749        while ((p = strsep(&options, ",")) != NULL) {
 750                int token;
 751                if (!*p)
 752                        continue;
 753
 754                token = match_token(p, tokens, args);
 755                switch (token) {
 756                case Opt_uid:
 757                        if (match_int(&args[0], &option))
 758                                goto bad_val;
 759                        pconfig->uid = option;
 760                        break;
 761
 762                case Opt_gid:
 763                        if (match_int(&args[0], &option))
 764                                goto bad_val;
 765                        pconfig->gid = option;
 766                        break;
 767
 768                case Opt_mode:
 769                        if (match_octal(&args[0], &option))
 770                                goto bad_val;
 771                        pconfig->mode = option & 0777U;
 772                        break;
 773
 774                case Opt_size: {
 775                        unsigned long long size;
 776                        /* memparse() will accept a K/M/G without a digit */
 777                        if (!isdigit(*args[0].from))
 778                                goto bad_val;
 779                        size = memparse(args[0].from, &rest);
 780                        if (*rest == '%') {
 781                                size <<= HPAGE_SHIFT;
 782                                size *= max_huge_pages;
 783                                do_div(size, 100);
 784                        }
 785                        pconfig->nr_blocks = (size >> HPAGE_SHIFT);
 786                        break;
 787                }
 788
 789                case Opt_nr_inodes:
 790                        /* memparse() will accept a K/M/G without a digit */
 791                        if (!isdigit(*args[0].from))
 792                                goto bad_val;
 793                        pconfig->nr_inodes = memparse(args[0].from, &rest);
 794                        break;
 795
 796                default:
 797                        printk(KERN_ERR "hugetlbfs: Bad mount option: \"%s\"\n",
 798                                 p);
 799                        return -EINVAL;
 800                        break;
 801                }
 802        }
 803        return 0;
 804
 805bad_val:
 806        printk(KERN_ERR "hugetlbfs: Bad value '%s' for mount option '%s'\n",
 807               args[0].from, p);
 808        return 1;
 809}
 810
 811static int
 812hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
 813{
 814        struct inode * inode;
 815        struct dentry * root;
 816        int ret;
 817        struct hugetlbfs_config config;
 818        struct hugetlbfs_sb_info *sbinfo;
 819
 820        config.nr_blocks = -1; /* No limit on size by default */
 821        config.nr_inodes = -1; /* No limit on number of inodes by default */
 822        config.uid = current->fsuid;
 823        config.gid = current->fsgid;
 824        config.mode = 0755;
 825        ret = hugetlbfs_parse_options(data, &config);
 826        if (ret)
 827                return ret;
 828
 829        sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
 830        if (!sbinfo)
 831                return -ENOMEM;
 832        sb->s_fs_info = sbinfo;
 833        spin_lock_init(&sbinfo->stat_lock);
 834        sbinfo->max_blocks = config.nr_blocks;
 835        sbinfo->free_blocks = config.nr_blocks;
 836        sbinfo->max_inodes = config.nr_inodes;
 837        sbinfo->free_inodes = config.nr_inodes;
 838        sb->s_maxbytes = MAX_LFS_FILESIZE;
 839        sb->s_blocksize = HPAGE_SIZE;
 840        sb->s_blocksize_bits = HPAGE_SHIFT;
 841        sb->s_magic = HUGETLBFS_MAGIC;
 842        sb->s_op = &hugetlbfs_ops;
 843        sb->s_time_gran = 1;
 844        inode = hugetlbfs_get_inode(sb, config.uid, config.gid,
 845                                        S_IFDIR | config.mode, 0);
 846        if (!inode)
 847                goto out_free;
 848
 849        root = d_alloc_root(inode);
 850        if (!root) {
 851                iput(inode);
 852                goto out_free;
 853        }
 854        sb->s_root = root;
 855        return 0;
 856out_free:
 857        kfree(sbinfo);
 858        return -ENOMEM;
 859}
 860
 861int hugetlb_get_quota(struct address_space *mapping, long delta)
 862{
 863        int ret = 0;
 864        struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
 865
 866        if (sbinfo->free_blocks > -1) {
 867                spin_lock(&sbinfo->stat_lock);
 868                if (sbinfo->free_blocks - delta >= 0)
 869                        sbinfo->free_blocks -= delta;
 870                else
 871                        ret = -ENOMEM;
 872                spin_unlock(&sbinfo->stat_lock);
 873        }
 874
 875        return ret;
 876}
 877
 878void hugetlb_put_quota(struct address_space *mapping, long delta)
 879{
 880        struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
 881
 882        if (sbinfo->free_blocks > -1) {
 883                spin_lock(&sbinfo->stat_lock);
 884                sbinfo->free_blocks += delta;
 885                spin_unlock(&sbinfo->stat_lock);
 886        }
 887}
 888
 889static int hugetlbfs_get_sb(struct file_system_type *fs_type,
 890        int flags, const char *dev_name, void *data, struct vfsmount *mnt)
 891{
 892        return get_sb_nodev(fs_type, flags, data, hugetlbfs_fill_super, mnt);
 893}
 894
 895static struct file_system_type hugetlbfs_fs_type = {
 896        .name           = "hugetlbfs",
 897        .get_sb         = hugetlbfs_get_sb,
 898        .kill_sb        = kill_litter_super,
 899};
 900
 901static struct vfsmount *hugetlbfs_vfsmount;
 902
 903static int can_do_hugetlb_shm(void)
 904{
 905        return likely(capable(CAP_IPC_LOCK) ||
 906                        in_group_p(sysctl_hugetlb_shm_group) ||
 907                        can_do_mlock());
 908}
 909
 910struct file *hugetlb_file_setup(const char *name, size_t size)
 911{
 912        int error = -ENOMEM;
 913        struct file *file;
 914        struct inode *inode;
 915        struct dentry *dentry, *root;
 916        struct qstr quick_string;
 917
 918        if (!hugetlbfs_vfsmount)
 919                return ERR_PTR(-ENOENT);
 920
 921        if (!can_do_hugetlb_shm())
 922                return ERR_PTR(-EPERM);
 923
 924        if (!user_shm_lock(size, current->user))
 925                return ERR_PTR(-ENOMEM);
 926
 927        root = hugetlbfs_vfsmount->mnt_root;
 928        quick_string.name = name;
 929        quick_string.len = strlen(quick_string.name);
 930        quick_string.hash = 0;
 931        dentry = d_alloc(root, &quick_string);
 932        if (!dentry)
 933                goto out_shm_unlock;
 934
 935        error = -ENOSPC;
 936        inode = hugetlbfs_get_inode(root->d_sb, current->fsuid,
 937                                current->fsgid, S_IFREG | S_IRWXUGO, 0);
 938        if (!inode)
 939                goto out_dentry;
 940
 941        error = -ENOMEM;
 942        if (hugetlb_reserve_pages(inode, 0, size >> HPAGE_SHIFT))
 943                goto out_inode;
 944
 945        d_instantiate(dentry, inode);
 946        inode->i_size = size;
 947        inode->i_nlink = 0;
 948
 949        error = -ENFILE;
 950        file = alloc_file(hugetlbfs_vfsmount, dentry,
 951                        FMODE_WRITE | FMODE_READ,
 952                        &hugetlbfs_file_operations);
 953        if (!file)
 954                goto out_inode;
 955
 956        return file;
 957
 958out_inode:
 959        iput(inode);
 960out_dentry:
 961        dput(dentry);
 962out_shm_unlock:
 963        user_shm_unlock(size, current->user);
 964        return ERR_PTR(error);
 965}
 966
 967static int __init init_hugetlbfs_fs(void)
 968{
 969        int error;
 970        struct vfsmount *vfsmount;
 971
 972        error = bdi_init(&hugetlbfs_backing_dev_info);
 973        if (error)
 974                return error;
 975
 976        hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
 977                                        sizeof(struct hugetlbfs_inode_info),
 978                                        0, 0, init_once);
 979        if (hugetlbfs_inode_cachep == NULL)
 980                goto out2;
 981
 982        error = register_filesystem(&hugetlbfs_fs_type);
 983        if (error)
 984                goto out;
 985
 986        vfsmount = kern_mount(&hugetlbfs_fs_type);
 987
 988        if (!IS_ERR(vfsmount)) {
 989                hugetlbfs_vfsmount = vfsmount;
 990                return 0;
 991        }
 992
 993        error = PTR_ERR(vfsmount);
 994
 995 out:
 996        if (error)
 997                kmem_cache_destroy(hugetlbfs_inode_cachep);
 998 out2:
 999        bdi_destroy(&hugetlbfs_backing_dev_info);
1000        return error;
1001}
1002
1003static void __exit exit_hugetlbfs_fs(void)
1004{
1005        kmem_cache_destroy(hugetlbfs_inode_cachep);
1006        unregister_filesystem(&hugetlbfs_fs_type);
1007        bdi_destroy(&hugetlbfs_backing_dev_info);
1008}
1009
1010module_init(init_hugetlbfs_fs)
1011module_exit(exit_hugetlbfs_fs)
1012
1013MODULE_LICENSE("GPL");
1014