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/*
* linux/fs/bad_inode.c
*
* Copyright (C) 1997, Stephen Tweedie
*
* Provide stub functions for unreadable inodes
*/
#include <linux/fs.h>
#include <linux/stat.h>
#include <linux/sched.h>
/*
* The follow_link operation is special: it must behave as a no-op
* so that a bad root inode can at least be unmounted. To do this
* we must dput() the base and return the dentry with a dget().
*/
static struct dentry * bad_follow_link(struct dentry *dent, struct dentry *base)
{
dput(base);
return dget(dent);
}
static int return_EIO(void)
{
return -EIO;
}
#define EIO_ERROR ((void *) (return_EIO))
static struct file_operations bad_file_ops =
{
EIO_ERROR, /* lseek */
EIO_ERROR, /* read */
EIO_ERROR, /* write */
EIO_ERROR, /* readdir */
EIO_ERROR, /* select */
EIO_ERROR, /* ioctl */
EIO_ERROR, /* mmap */
EIO_ERROR, /* open */
EIO_ERROR, /* release */
EIO_ERROR, /* fsync */
EIO_ERROR, /* fasync */
EIO_ERROR, /* check_media_change */
EIO_ERROR /* revalidate */
};
struct inode_operations bad_inode_ops =
{
&bad_file_ops, /* default file operations */
EIO_ERROR, /* create */
EIO_ERROR, /* lookup */
EIO_ERROR, /* link */
EIO_ERROR, /* unlink */
EIO_ERROR, /* symlink */
EIO_ERROR, /* mkdir */
EIO_ERROR, /* rmdir */
EIO_ERROR, /* mknod */
EIO_ERROR, /* rename */
EIO_ERROR, /* readlink */
bad_follow_link, /* follow_link */
EIO_ERROR, /* readpage */
EIO_ERROR, /* writepage */
EIO_ERROR, /* bmap */
EIO_ERROR, /* truncate */
EIO_ERROR, /* permission */
EIO_ERROR, /* smap */
EIO_ERROR, /* update_page */
EIO_ERROR /* revalidate */
};
/*
* 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)
{
inode->i_mode = S_IFREG;
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
inode->i_op = &bad_inode_ops;
}
/*
* 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);
}
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