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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 int bad_follow_link(struct dentry *dent, struct nameidata *nd)
{
return vfs_follow_link(nd, ERR_PTR(-EIO));
}
static int return_EIO(void)
{
return -EIO;
}
#define EIO_ERROR ((void *) (return_EIO))
static struct file_operations bad_file_ops =
{
llseek: EIO_ERROR,
read: EIO_ERROR,
write: EIO_ERROR,
readdir: EIO_ERROR,
poll: EIO_ERROR,
ioctl: EIO_ERROR,
mmap: EIO_ERROR,
open: EIO_ERROR,
flush: EIO_ERROR,
release: EIO_ERROR,
fsync: EIO_ERROR,
fasync: EIO_ERROR,
lock: EIO_ERROR,
};
struct inode_operations bad_inode_ops =
{
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: EIO_ERROR,
follow_link: bad_follow_link,
truncate: EIO_ERROR,
permission: EIO_ERROR,
revalidate: EIO_ERROR,
};
/*
* 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.
*/
/**
* make_bad_inode - mark an inode bad due to an I/O error
* @inode: Inode to mark bad
*
* When an inode cannot be read due to a media or remote network
* failure this function makes the inode "bad" and causes I/O operations
* on it to fail from this point on.
*/
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;
inode->i_fop = &bad_file_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.
*/
/**
* is_bad_inode - is an inode errored
* @inode: inode to test
*
* Returns true if the inode in question has been marked as bad.
*/
int is_bad_inode(struct inode * inode)
{
return (inode->i_op == &bad_inode_ops);
}
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