bad_inode.c

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/*
 *  linux/fs/bad_inode.c
 *
 *  Copyright (C) 1997, Stephen Tweedie
 *
 *  Provide stub functions for unreadable inodes
 *
 *  Fabian Frederick : August 2003 - All file operations assigned to EIO
 */

#include <linux/fs.h>
#include <linux/export.h>
#include <linux/stat.h>
#include <linux/time.h>
#include <linux/namei.h>
#include <linux/poll.h>


static loff_t bad_file_llseek(struct file *file, loff_t offset, int origin)
{
    return -EIO;
}

static ssize_t bad_file_read(struct file *filp, char __user *buf,
            size_t size, loff_t *ppos)
{
        return -EIO;
}

static ssize_t bad_file_write(struct file *filp, const char __user *buf,
            size_t siz, loff_t *ppos)
{
        return -EIO;
}

static ssize_t bad_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
            unsigned long nr_segs, loff_t pos)
{
    return -EIO;
}

static ssize_t bad_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
            unsigned long nr_segs, loff_t pos)
{
    return -EIO;
}

static int bad_file_readdir(struct file *filp, void *dirent, filldir_t filldir)
{
    return -EIO;
}

static unsigned int bad_file_poll(struct file *filp, poll_table *wait)
{
    return POLLERR;
}

static long bad_file_unlocked_ioctl(struct file *file, unsigned cmd,
            unsigned long arg)
{
    return -EIO;
}

static long bad_file_compat_ioctl(struct file *file, unsigned int cmd,
            unsigned long arg)
{
    return -EIO;
}

static int bad_file_mmap(struct file *file, struct vm_area_struct *vma)
{
    return -EIO;
}

static int bad_file_open(struct inode *inode, struct file *filp)
{
    return -EIO;
}

static int bad_file_flush(struct file *file, fl_owner_t id)
{
    return -EIO;
}

static int bad_file_release(struct inode *inode, struct file *filp)
{
    return -EIO;
}

static int bad_file_fsync(struct file *file, loff_t start, loff_t end,
              int datasync)
{
    return -EIO;
}

static int bad_file_aio_fsync(struct kiocb *iocb, int datasync)
{
    return -EIO;
}

static int bad_file_fasync(int fd, struct file *filp, int on)
{
    return -EIO;
}

static int bad_file_lock(struct file *file, int cmd, struct file_lock *fl)
{
    return -EIO;
}

static ssize_t bad_file_sendpage(struct file *file, struct page *page,
            int off, size_t len, loff_t *pos, int more)
{
    return -EIO;
}

static unsigned long bad_file_get_unmapped_area(struct file *file,
                unsigned long addr, unsigned long len,
                unsigned long pgoff, unsigned long flags)
{
    return -EIO;
}

static int bad_file_check_flags(int flags)
{
    return -EIO;
}

static int bad_file_flock(struct file *filp, int cmd, struct file_lock *fl)
{
    return -EIO;
}

static ssize_t bad_file_splice_write(struct pipe_inode_info *pipe,
            struct file *out, loff_t *ppos, size_t len,
            unsigned int flags)
{
    return -EIO;
}

static ssize_t bad_file_splice_read(struct file *in, loff_t *ppos,
            struct pipe_inode_info *pipe, size_t len,
            unsigned int flags)
{
    return -EIO;
}

static const struct file_operations bad_file_ops =
{
    .llseek     = bad_file_llseek,
    .read       = bad_file_read,
    .write      = bad_file_write,
    .aio_read   = bad_file_aio_read,
    .aio_write  = bad_file_aio_write,
    .readdir    = bad_file_readdir,
    .poll       = bad_file_poll,
    .unlocked_ioctl = bad_file_unlocked_ioctl,
    .compat_ioctl   = bad_file_compat_ioctl,
    .mmap       = bad_file_mmap,
    .open       = bad_file_open,
    .flush      = bad_file_flush,
    .release    = bad_file_release,
    .fsync      = bad_file_fsync,
    .aio_fsync  = bad_file_aio_fsync,
    .fasync     = bad_file_fasync,
    .lock       = bad_file_lock,
    .sendpage   = bad_file_sendpage,
    .get_unmapped_area = bad_file_get_unmapped_area,
    .check_flags    = bad_file_check_flags,
    .flock      = bad_file_flock,
    .splice_write   = bad_file_splice_write,
    .splice_read    = bad_file_splice_read,
};

static int bad_inode_create (struct inode *dir, struct dentry *dentry,
        umode_t mode, bool excl)
{
    return -EIO;
}

static struct dentry *bad_inode_lookup(struct inode *dir,
            struct dentry *dentry, unsigned int flags)
{
    return ERR_PTR(-EIO);
}

static int bad_inode_link (struct dentry *old_dentry, struct inode *dir,
        struct dentry *dentry)
{
    return -EIO;
}

static int bad_inode_unlink(struct inode *dir, struct dentry *dentry)
{
    return -EIO;
}

static int bad_inode_symlink (struct inode *dir, struct dentry *dentry,
        const char *symname)
{
    return -EIO;
}

static int bad_inode_mkdir(struct inode *dir, struct dentry *dentry,
            umode_t mode)
{
    return -EIO;
}

static int bad_inode_rmdir (struct inode *dir, struct dentry *dentry)
{
    return -EIO;
}

static int bad_inode_mknod (struct inode *dir, struct dentry *dentry,
            umode_t mode, dev_t rdev)
{
    return -EIO;
}

static int bad_inode_rename (struct inode *old_dir, struct dentry *old_dentry,
        struct inode *new_dir, struct dentry *new_dentry)
{
    return -EIO;
}

static int bad_inode_readlink(struct dentry *dentry, char __user *buffer,
        int buflen)
{
    return -EIO;
}

static int bad_inode_permission(struct inode *inode, int mask)
{
    return -EIO;
}

static int bad_inode_getattr(struct vfsmount *mnt, struct dentry *dentry,
            struct kstat *stat)
{
    return -EIO;
}

static int bad_inode_setattr(struct dentry *direntry, struct iattr *attrs)
{
    return -EIO;
}

static int bad_inode_setxattr(struct dentry *dentry, const char *name,
        const void *value, size_t size, int flags)
{
    return -EIO;
}

static ssize_t bad_inode_getxattr(struct dentry *dentry, const char *name,
            void *buffer, size_t size)
{
    return -EIO;
}

static ssize_t bad_inode_listxattr(struct dentry *dentry, char *buffer,
            size_t buffer_size)
{
    return -EIO;
}

static int bad_inode_removexattr(struct dentry *dentry, const char *name)
{
    return -EIO;
}

static const struct inode_operations bad_inode_ops =
{
    .create     = bad_inode_create,
    .lookup     = bad_inode_lookup,
    .link       = bad_inode_link,
    .unlink     = bad_inode_unlink,
    .symlink    = bad_inode_symlink,
    .mkdir      = bad_inode_mkdir,
    .rmdir      = bad_inode_rmdir,
    .mknod      = bad_inode_mknod,
    .rename     = bad_inode_rename,
    .readlink   = bad_inode_readlink,
    /* follow_link must be no-op, otherwise unmounting this inode
       won't work */
    /* put_link returns void */
    /* truncate returns void */
    .permission = bad_inode_permission,
    .getattr    = bad_inode_getattr,
    .setattr    = bad_inode_setattr,
    .setxattr   = bad_inode_setxattr,
    .getxattr   = bad_inode_getxattr,
    .listxattr  = bad_inode_listxattr,
    .removexattr    = bad_inode_removexattr,
};


/*
 * When a filesystem is unable to read an inode due to an I/O error in
 * its read_inode() function, it can call make_bad_inode() to return a
 * set of stubs which will return EIO errors as required. 
 *
 * We only need to do limited initialisation: all other fields are
 * preinitialised to zero automatically.
 */
 
void make_bad_inode(struct inode *inode)
{
    remove_inode_hash(inode);

    inode->i_mode = S_IFREG;
    inode->i_atime = inode->i_mtime = inode->i_ctime =
        current_fs_time(inode->i_sb);
    inode->i_op = &bad_inode_ops;   
    inode->i_fop = &bad_file_ops;   
}
EXPORT_SYMBOL(make_bad_inode);

/*
 * This tests whether an inode has been flagged as bad. The test uses
 * &bad_inode_ops to cover the case of invalidated inodes as well as
 * those created by make_bad_inode() above.
 */
 
int is_bad_inode(struct inode *inode)
{
    return (inode->i_op == &bad_inode_ops); 
}

EXPORT_SYMBOL(is_bad_inode);

void iget_failed(struct inode *inode)
{
    make_bad_inode(inode);
    unlock_new_inode(inode);
    iput(inode);
}
EXPORT_SYMBOL(iget_failed);