libfs.c

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/*
 *  fs/libfs.c
 *  Library for filesystems writers.
 */

#include <linux/export.h>
#include <linux/pagemap.h>
#include <linux/slab.h>
#include <linux/mount.h>
#include <linux/vfs.h>
#include <linux/quotaops.h>
#include <linux/mutex.h>
#include <linux/exportfs.h>
#include <linux/writeback.h>
#include <linux/buffer_head.h> /* sync_mapping_buffers */

#include <asm/uaccess.h>

#include "internal.h"

static inline int simple_positive(struct dentry *dentry)
{
    return dentry->d_inode && !d_unhashed(dentry);
}

int simple_getattr(struct vfsmount *mnt, struct dentry *dentry,
           struct kstat *stat)
{
    struct inode *inode = dentry->d_inode;
    generic_fillattr(inode, stat);
    stat->blocks = inode->i_mapping->nrpages << (PAGE_CACHE_SHIFT - 9);
    return 0;
}

int simple_statfs(struct dentry *dentry, struct kstatfs *buf)
{
    buf->f_type = dentry->d_sb->s_magic;
    buf->f_bsize = PAGE_CACHE_SIZE;
    buf->f_namelen = NAME_MAX;
    return 0;
}

/*
 * Retaining negative dentries for an in-memory filesystem just wastes
 * memory and lookup time: arrange for them to be deleted immediately.
 */
static int simple_delete_dentry(const struct dentry *dentry)
{
    return 1;
}

/*
 * Lookup the data. This is trivial - if the dentry didn't already
 * exist, we know it is negative.  Set d_op to delete negative dentries.
 */
struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
{
    static const struct dentry_operations simple_dentry_operations = {
        .d_delete = simple_delete_dentry,
    };

    if (dentry->d_name.len > NAME_MAX)
        return ERR_PTR(-ENAMETOOLONG);
    d_set_d_op(dentry, &simple_dentry_operations);
    d_add(dentry, NULL);
    return NULL;
}

int dcache_dir_open(struct inode *inode, struct file *file)
{
    static struct qstr cursor_name = QSTR_INIT(".", 1);

    file->private_data = d_alloc(file->f_path.dentry, &cursor_name);

    return file->private_data ? 0 : -ENOMEM;
}

int dcache_dir_close(struct inode *inode, struct file *file)
{
    dput(file->private_data);
    return 0;
}

loff_t dcache_dir_lseek(struct file *file, loff_t offset, int origin)
{
    struct dentry *dentry = file->f_path.dentry;
    mutex_lock(&dentry->d_inode->i_mutex);
    switch (origin) {
        case 1:
            offset += file->f_pos;
        case 0:
            if (offset >= 0)
                break;
        default:
            mutex_unlock(&dentry->d_inode->i_mutex);
            return -EINVAL;
    }
    if (offset != file->f_pos) {
        file->f_pos = offset;
        if (file->f_pos >= 2) {
            struct list_head *p;
            struct dentry *cursor = file->private_data;
            loff_t n = file->f_pos - 2;

            spin_lock(&dentry->d_lock);
            /* d_lock not required for cursor */
            list_del(&cursor->d_u.d_child);
            p = dentry->d_subdirs.next;
            while (n && p != &dentry->d_subdirs) {
                struct dentry *next;
                next = list_entry(p, struct dentry, d_u.d_child);
                spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED);
                if (simple_positive(next))
                    n--;
                spin_unlock(&next->d_lock);
                p = p->next;
            }
            list_add_tail(&cursor->d_u.d_child, p);
            spin_unlock(&dentry->d_lock);
        }
    }
    mutex_unlock(&dentry->d_inode->i_mutex);
    return offset;
}

/* Relationship between i_mode and the DT_xxx types */
static inline unsigned char dt_type(struct inode *inode)
{
    return (inode->i_mode >> 12) & 15;
}

/*
 * Directory is locked and all positive dentries in it are safe, since
 * for ramfs-type trees they can't go away without unlink() or rmdir(),
 * both impossible due to the lock on directory.
 */

int dcache_readdir(struct file * filp, void * dirent, filldir_t filldir)
{
    struct dentry *dentry = filp->f_path.dentry;
    struct dentry *cursor = filp->private_data;
    struct list_head *p, *q = &cursor->d_u.d_child;
    ino_t ino;
    int i = filp->f_pos;

    switch (i) {
        case 0:
            ino = dentry->d_inode->i_ino;
            if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
                break;
            filp->f_pos++;
            i++;
            /* fallthrough */
        case 1:
            ino = parent_ino(dentry);
            if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
                break;
            filp->f_pos++;
            i++;
            /* fallthrough */
        default:
            spin_lock(&dentry->d_lock);
            if (filp->f_pos == 2)
                list_move(q, &dentry->d_subdirs);

            for (p=q->next; p != &dentry->d_subdirs; p=p->next) {
                struct dentry *next;
                next = list_entry(p, struct dentry, d_u.d_child);
                spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED);
                if (!simple_positive(next)) {
                    spin_unlock(&next->d_lock);
                    continue;
                }

                spin_unlock(&next->d_lock);
                spin_unlock(&dentry->d_lock);
                if (filldir(dirent, next->d_name.name, 
                        next->d_name.len, filp->f_pos, 
                        next->d_inode->i_ino, 
                        dt_type(next->d_inode)) < 0)
                    return 0;
                spin_lock(&dentry->d_lock);
                spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED);
                /* next is still alive */
                list_move(q, p);
                spin_unlock(&next->d_lock);
                p = q;
                filp->f_pos++;
            }
            spin_unlock(&dentry->d_lock);
    }
    return 0;
}

ssize_t generic_read_dir(struct file *filp, char __user *buf, size_t siz, loff_t *ppos)
{
    return -EISDIR;
}

const struct file_operations simple_dir_operations = {
    .open       = dcache_dir_open,
    .release    = dcache_dir_close,
    .llseek     = dcache_dir_lseek,
    .read       = generic_read_dir,
    .readdir    = dcache_readdir,
    .fsync      = noop_fsync,
};

const struct inode_operations simple_dir_inode_operations = {
    .lookup     = simple_lookup,
};

static const struct super_operations simple_super_operations = {
    .statfs     = simple_statfs,
};

/*
 * Common helper for pseudo-filesystems (sockfs, pipefs, bdev - stuff that
 * will never be mountable)
 */
struct dentry *mount_pseudo(struct file_system_type *fs_type, char *name,
    const struct super_operations *ops,
    const struct dentry_operations *dops, unsigned long magic)
{
    struct super_block *s;
    struct dentry *dentry;
    struct inode *root;
    struct qstr d_name = QSTR_INIT(name, strlen(name));

    s = sget(fs_type, NULL, set_anon_super, MS_NOUSER, NULL);
    if (IS_ERR(s))
        return ERR_CAST(s);

    s->s_maxbytes = MAX_LFS_FILESIZE;
    s->s_blocksize = PAGE_SIZE;
    s->s_blocksize_bits = PAGE_SHIFT;
    s->s_magic = magic;
    s->s_op = ops ? ops : &simple_super_operations;
    s->s_time_gran = 1;
    root = new_inode(s);
    if (!root)
        goto Enomem;
    /*
     * since this is the first inode, make it number 1. New inodes created
     * after this must take care not to collide with it (by passing
     * max_reserved of 1 to iunique).
     */
    root->i_ino = 1;
    root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR;
    root->i_atime = root->i_mtime = root->i_ctime = CURRENT_TIME;
    dentry = __d_alloc(s, &d_name);
    if (!dentry) {
        iput(root);
        goto Enomem;
    }
    d_instantiate(dentry, root);
    s->s_root = dentry;
    s->s_d_op = dops;
    s->s_flags |= MS_ACTIVE;
    return dget(s->s_root);

Enomem:
    deactivate_locked_super(s);
    return ERR_PTR(-ENOMEM);
}

int simple_open(struct inode *inode, struct file *file)
{
    if (inode->i_private)
        file->private_data = inode->i_private;
    return 0;
}

int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
{
    struct inode *inode = old_dentry->d_inode;

    inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
    inc_nlink(inode);
    ihold(inode);
    dget(dentry);
    d_instantiate(dentry, inode);
    return 0;
}

int simple_empty(struct dentry *dentry)
{
    struct dentry *child;
    int ret = 0;

    spin_lock(&dentry->d_lock);
    list_for_each_entry(child, &dentry->d_subdirs, d_u.d_child) {
        spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED);
        if (simple_positive(child)) {
            spin_unlock(&child->d_lock);
            goto out;
        }
        spin_unlock(&child->d_lock);
    }
    ret = 1;
out:
    spin_unlock(&dentry->d_lock);
    return ret;
}

int simple_unlink(struct inode *dir, struct dentry *dentry)
{
    struct inode *inode = dentry->d_inode;

    inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
    drop_nlink(inode);
    dput(dentry);
    return 0;
}

int simple_rmdir(struct inode *dir, struct dentry *dentry)
{
    if (!simple_empty(dentry))
        return -ENOTEMPTY;

    drop_nlink(dentry->d_inode);
    simple_unlink(dir, dentry);
    drop_nlink(dir);
    return 0;
}

int simple_rename(struct inode *old_dir, struct dentry *old_dentry,
        struct inode *new_dir, struct dentry *new_dentry)
{
    struct inode *inode = old_dentry->d_inode;
    int they_are_dirs = S_ISDIR(old_dentry->d_inode->i_mode);

    if (!simple_empty(new_dentry))
        return -ENOTEMPTY;

    if (new_dentry->d_inode) {
        simple_unlink(new_dir, new_dentry);
        if (they_are_dirs) {
            drop_nlink(new_dentry->d_inode);
            drop_nlink(old_dir);
        }
    } else if (they_are_dirs) {
        drop_nlink(old_dir);
        inc_nlink(new_dir);
    }

    old_dir->i_ctime = old_dir->i_mtime = new_dir->i_ctime =
        new_dir->i_mtime = inode->i_ctime = CURRENT_TIME;

    return 0;
}

int simple_setattr(struct dentry *dentry, struct iattr *iattr)
{
    struct inode *inode = dentry->d_inode;
    int error;

    WARN_ON_ONCE(inode->i_op->truncate);

    error = inode_change_ok(inode, iattr);
    if (error)
        return error;

    if (iattr->ia_valid & ATTR_SIZE)
        truncate_setsize(inode, iattr->ia_size);
    setattr_copy(inode, iattr);
    mark_inode_dirty(inode);
    return 0;
}
EXPORT_SYMBOL(simple_setattr);

int simple_readpage(struct file *file, struct page *page)
{
    clear_highpage(page);
    flush_dcache_page(page);
    SetPageUptodate(page);
    unlock_page(page);
    return 0;
}

int simple_write_begin(struct file *file, struct address_space *mapping,
            loff_t pos, unsigned len, unsigned flags,
            struct page **pagep, void **fsdata)
{
    struct page *page;
    pgoff_t index;

    index = pos >> PAGE_CACHE_SHIFT;

    page = grab_cache_page_write_begin(mapping, index, flags);
    if (!page)
        return -ENOMEM;

    *pagep = page;

    if (!PageUptodate(page) && (len != PAGE_CACHE_SIZE)) {
        unsigned from = pos & (PAGE_CACHE_SIZE - 1);

        zero_user_segments(page, 0, from, from + len, PAGE_CACHE_SIZE);
    }
    return 0;
}

int simple_write_end(struct file *file, struct address_space *mapping,
            loff_t pos, unsigned len, unsigned copied,
            struct page *page, void *fsdata)
{
    struct inode *inode = page->mapping->host;
    loff_t last_pos = pos + copied;

    /* zero the stale part of the page if we did a short copy */
    if (copied < len) {
        unsigned from = pos & (PAGE_CACHE_SIZE - 1);

        zero_user(page, from + copied, len - copied);
    }

    if (!PageUptodate(page))
        SetPageUptodate(page);
    /*
     * No need to use i_size_read() here, the i_size
     * cannot change under us because we hold the i_mutex.
     */
    if (last_pos > inode->i_size)
        i_size_write(inode, last_pos);

    set_page_dirty(page);
    unlock_page(page);
    page_cache_release(page);

    return copied;
}

/*
 * the inodes created here are not hashed. If you use iunique to generate
 * unique inode values later for this filesystem, then you must take care
 * to pass it an appropriate max_reserved value to avoid collisions.
 */
int simple_fill_super(struct super_block *s, unsigned long magic,
              struct tree_descr *files)
{
    struct inode *inode;
    struct dentry *root;
    struct dentry *dentry;
    int i;

    s->s_blocksize = PAGE_CACHE_SIZE;
    s->s_blocksize_bits = PAGE_CACHE_SHIFT;
    s->s_magic = magic;
    s->s_op = &simple_super_operations;
    s->s_time_gran = 1;

    inode = new_inode(s);
    if (!inode)
        return -ENOMEM;
    /*
     * because the root inode is 1, the files array must not contain an
     * entry at index 1
     */
    inode->i_ino = 1;
    inode->i_mode = S_IFDIR | 0755;
    inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
    inode->i_op = &simple_dir_inode_operations;
    inode->i_fop = &simple_dir_operations;
    set_nlink(inode, 2);
    root = d_make_root(inode);
    if (!root)
        return -ENOMEM;
    for (i = 0; !files->name || files->name[0]; i++, files++) {
        if (!files->name)
            continue;

        /* warn if it tries to conflict with the root inode */
        if (unlikely(i == 1))
            printk(KERN_WARNING "%s: %s passed in a files array"
                "with an index of 1!\n", __func__,
                s->s_type->name);

        dentry = d_alloc_name(root, files->name);
        if (!dentry)
            goto out;
        inode = new_inode(s);
        if (!inode) {
            dput(dentry);
            goto out;
        }
        inode->i_mode = S_IFREG | files->mode;
        inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
        inode->i_fop = files->ops;
        inode->i_ino = i;
        d_add(dentry, inode);
    }
    s->s_root = root;
    return 0;
out:
    d_genocide(root);
    shrink_dcache_parent(root);
    dput(root);
    return -ENOMEM;
}

static DEFINE_SPINLOCK(pin_fs_lock);

int simple_pin_fs(struct file_system_type *type, struct vfsmount **mount, int *count)
{
    struct vfsmount *mnt = NULL;
    spin_lock(&pin_fs_lock);
    if (unlikely(!*mount)) {
        spin_unlock(&pin_fs_lock);
        mnt = vfs_kern_mount(type, MS_KERNMOUNT, type->name, NULL);
        if (IS_ERR(mnt))
            return PTR_ERR(mnt);
        spin_lock(&pin_fs_lock);
        if (!*mount)
            *mount = mnt;
    }
    mntget(*mount);
    ++*count;
    spin_unlock(&pin_fs_lock);
    mntput(mnt);
    return 0;
}

void simple_release_fs(struct vfsmount **mount, int *count)
{
    struct vfsmount *mnt;
    spin_lock(&pin_fs_lock);
    mnt = *mount;
    if (!--*count)
        *mount = NULL;
    spin_unlock(&pin_fs_lock);
    mntput(mnt);
}

ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos,
                const void *from, size_t available)
{
    loff_t pos = *ppos;
    size_t ret;

    if (pos < 0)
        return -EINVAL;
    if (pos >= available || !count)
        return 0;
    if (count > available - pos)
        count = available - pos;
    ret = copy_to_user(to, from + pos, count);
    if (ret == count)
        return -EFAULT;
    count -= ret;
    *ppos = pos + count;
    return count;
}

ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos,
        const void __user *from, size_t count)
{
    loff_t pos = *ppos;
    size_t res;

    if (pos < 0)
        return -EINVAL;
    if (pos >= available || !count)
        return 0;
    if (count > available - pos)
        count = available - pos;
    res = copy_from_user(to + pos, from, count);
    if (res == count)
        return -EFAULT;
    count -= res;
    *ppos = pos + count;
    return count;
}

ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos,
                const void *from, size_t available)
{
    loff_t pos = *ppos;

    if (pos < 0)
        return -EINVAL;
    if (pos >= available)
        return 0;
    if (count > available - pos)
        count = available - pos;
    memcpy(to, from + pos, count);
    *ppos = pos + count;

    return count;
}

/*
 * Transaction based IO.
 * The file expects a single write which triggers the transaction, and then
 * possibly a read which collects the result - which is stored in a
 * file-local buffer.
 */

void simple_transaction_set(struct file *file, size_t n)
{
    struct simple_transaction_argresp *ar = file->private_data;

    BUG_ON(n > SIMPLE_TRANSACTION_LIMIT);

    /*
     * The barrier ensures that ar->size will really remain zero until
     * ar->data is ready for reading.
     */
    smp_mb();
    ar->size = n;
}

char *simple_transaction_get(struct file *file, const char __user *buf, size_t size)
{
    struct simple_transaction_argresp *ar;
    static DEFINE_SPINLOCK(simple_transaction_lock);

    if (size > SIMPLE_TRANSACTION_LIMIT - 1)
        return ERR_PTR(-EFBIG);

    ar = (struct simple_transaction_argresp *)get_zeroed_page(GFP_KERNEL);
    if (!ar)
        return ERR_PTR(-ENOMEM);

    spin_lock(&simple_transaction_lock);

    /* only one write allowed per open */
    if (file->private_data) {
        spin_unlock(&simple_transaction_lock);
        free_page((unsigned long)ar);
        return ERR_PTR(-EBUSY);
    }

    file->private_data = ar;

    spin_unlock(&simple_transaction_lock);

    if (copy_from_user(ar->data, buf, size))
        return ERR_PTR(-EFAULT);

    return ar->data;
}

ssize_t simple_transaction_read(struct file *file, char __user *buf, size_t size, loff_t *pos)
{
    struct simple_transaction_argresp *ar = file->private_data;

    if (!ar)
        return 0;
    return simple_read_from_buffer(buf, size, pos, ar->data, ar->size);
}

int simple_transaction_release(struct inode *inode, struct file *file)
{
    free_page((unsigned long)file->private_data);
    return 0;
}

/* Simple attribute files */

struct simple_attr {
    int (*get)(void *, u64 *);
    int (*set)(void *, u64);
    char get_buf[24];   /* enough to store a u64 and "\n\0" */
    char set_buf[24];
    void *data;
    const char *fmt;    /* format for read operation */
    struct mutex mutex; /* protects access to these buffers */
};

/* simple_attr_open is called by an actual attribute open file operation
 * to set the attribute specific access operations. */
int simple_attr_open(struct inode *inode, struct file *file,
             int (*get)(void *, u64 *), int (*set)(void *, u64),
             const char *fmt)
{
    struct simple_attr *attr;

    attr = kmalloc(sizeof(*attr), GFP_KERNEL);
    if (!attr)
        return -ENOMEM;

    attr->get = get;
    attr->set = set;
    attr->data = inode->i_private;
    attr->fmt = fmt;
    mutex_init(&attr->mutex);

    file->private_data = attr;

    return nonseekable_open(inode, file);
}

int simple_attr_release(struct inode *inode, struct file *file)
{
    kfree(file->private_data);
    return 0;
}

/* read from the buffer that is filled with the get function */
ssize_t simple_attr_read(struct file *file, char __user *buf,
             size_t len, loff_t *ppos)
{
    struct simple_attr *attr;
    size_t size;
    ssize_t ret;

    attr = file->private_data;

    if (!attr->get)
        return -EACCES;

    ret = mutex_lock_interruptible(&attr->mutex);
    if (ret)
        return ret;

    if (*ppos) {        /* continued read */
        size = strlen(attr->get_buf);
    } else {        /* first read */
        u64 val;
        ret = attr->get(attr->data, &val);
        if (ret)
            goto out;

        size = scnprintf(attr->get_buf, sizeof(attr->get_buf),
                 attr->fmt, (unsigned long long)val);
    }

    ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size);
out:
    mutex_unlock(&attr->mutex);
    return ret;
}

/* interpret the buffer as a number to call the set function with */
ssize_t simple_attr_write(struct file *file, const char __user *buf,
              size_t len, loff_t *ppos)
{
    struct simple_attr *attr;
    u64 val;
    size_t size;
    ssize_t ret;

    attr = file->private_data;
    if (!attr->set)
        return -EACCES;

    ret = mutex_lock_interruptible(&attr->mutex);
    if (ret)
        return ret;

    ret = -EFAULT;
    size = min(sizeof(attr->set_buf) - 1, len);
    if (copy_from_user(attr->set_buf, buf, size))
        goto out;

    attr->set_buf[size] = '\0';
    val = simple_strtoll(attr->set_buf, NULL, 0);
    ret = attr->set(attr->data, val);
    if (ret == 0)
        ret = len; /* on success, claim we got the whole input */
out:
    mutex_unlock(&attr->mutex);
    return ret;
}

struct dentry *generic_fh_to_dentry(struct super_block *sb, struct fid *fid,
        int fh_len, int fh_type, struct inode *(*get_inode)
            (struct super_block *sb, u64 ino, u32 gen))
{
    struct inode *inode = NULL;

    if (fh_len < 2)
        return NULL;

    switch (fh_type) {
    case FILEID_INO32_GEN:
    case FILEID_INO32_GEN_PARENT:
        inode = get_inode(sb, fid->i32.ino, fid->i32.gen);
        break;
    }

    return d_obtain_alias(inode);
}
EXPORT_SYMBOL_GPL(generic_fh_to_dentry);

struct dentry *generic_fh_to_parent(struct super_block *sb, struct fid *fid,
        int fh_len, int fh_type, struct inode *(*get_inode)
            (struct super_block *sb, u64 ino, u32 gen))
{
    struct inode *inode = NULL;

    if (fh_len <= 2)
        return NULL;

    switch (fh_type) {
    case FILEID_INO32_GEN_PARENT:
        inode = get_inode(sb, fid->i32.parent_ino,
                  (fh_len > 3 ? fid->i32.parent_gen : 0));
        break;
    }

    return d_obtain_alias(inode);
}
EXPORT_SYMBOL_GPL(generic_fh_to_parent);

int generic_file_fsync(struct file *file, loff_t start, loff_t end,
               int datasync)
{
    struct inode *inode = file->f_mapping->host;
    int err;
    int ret;

    err = filemap_write_and_wait_range(inode->i_mapping, start, end);
    if (err)
        return err;

    mutex_lock(&inode->i_mutex);
    ret = sync_mapping_buffers(inode->i_mapping);
    if (!(inode->i_state & I_DIRTY))
        goto out;
    if (datasync && !(inode->i_state & I_DIRTY_DATASYNC))
        goto out;

    err = sync_inode_metadata(inode, 1);
    if (ret == 0)
        ret = err;
out:
    mutex_unlock(&inode->i_mutex);
    return ret;
}
EXPORT_SYMBOL(generic_file_fsync);

int generic_check_addressable(unsigned blocksize_bits, u64 num_blocks)
{
    u64 last_fs_block = num_blocks - 1;
    u64 last_fs_page =
        last_fs_block >> (PAGE_CACHE_SHIFT - blocksize_bits);

    if (unlikely(num_blocks == 0))
        return 0;

    if ((blocksize_bits < 9) || (blocksize_bits > PAGE_CACHE_SHIFT))
        return -EINVAL;

    if ((last_fs_block > (sector_t)(~0ULL) >> (blocksize_bits - 9)) ||
        (last_fs_page > (pgoff_t)(~0ULL))) {
        return -EFBIG;
    }
    return 0;
}
EXPORT_SYMBOL(generic_check_addressable);

/*
 * No-op implementation of ->fsync for in-memory filesystems.
 */
int noop_fsync(struct file *file, loff_t start, loff_t end, int datasync)
{
    return 0;
}

EXPORT_SYMBOL(dcache_dir_close);
EXPORT_SYMBOL(dcache_dir_lseek);
EXPORT_SYMBOL(dcache_dir_open);
EXPORT_SYMBOL(dcache_readdir);
EXPORT_SYMBOL(generic_read_dir);
EXPORT_SYMBOL(mount_pseudo);
EXPORT_SYMBOL(simple_write_begin);
EXPORT_SYMBOL(simple_write_end);
EXPORT_SYMBOL(simple_dir_inode_operations);
EXPORT_SYMBOL(simple_dir_operations);
EXPORT_SYMBOL(simple_empty);
EXPORT_SYMBOL(simple_fill_super);
EXPORT_SYMBOL(simple_getattr);
EXPORT_SYMBOL(simple_open);
EXPORT_SYMBOL(simple_link);
EXPORT_SYMBOL(simple_lookup);
EXPORT_SYMBOL(simple_pin_fs);
EXPORT_SYMBOL(simple_readpage);
EXPORT_SYMBOL(simple_release_fs);
EXPORT_SYMBOL(simple_rename);
EXPORT_SYMBOL(simple_rmdir);
EXPORT_SYMBOL(simple_statfs);
EXPORT_SYMBOL(noop_fsync);
EXPORT_SYMBOL(simple_unlink);
EXPORT_SYMBOL(simple_read_from_buffer);
EXPORT_SYMBOL(simple_write_to_buffer);
EXPORT_SYMBOL(memory_read_from_buffer);
EXPORT_SYMBOL(simple_transaction_set);
EXPORT_SYMBOL(simple_transaction_get);
EXPORT_SYMBOL(simple_transaction_read);
EXPORT_SYMBOL(simple_transaction_release);
EXPORT_SYMBOL_GPL(simple_attr_open);
EXPORT_SYMBOL_GPL(simple_attr_release);
EXPORT_SYMBOL_GPL(simple_attr_read);
EXPORT_SYMBOL_GPL(simple_attr_write);