linux/fs/kernfs/kernfs-internal.h
Shaohua Li ba16b2846a kernfs: add an API to get kernfs node from inode number
Add an API to get kernfs node from inode number. We will need this to
implement exportfs operations.

This API will be used in blktrace too later, so it should be as fast as
possible. To make the API lock free, kernfs node is freed in RCU
context. And we depend on kernfs_node count/ino number to filter out
stale kernfs nodes.

Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-07-29 09:00:03 -06:00

117 lines
3.1 KiB
C

/*
* fs/kernfs/kernfs-internal.h - kernfs internal header file
*
* Copyright (c) 2001-3 Patrick Mochel
* Copyright (c) 2007 SUSE Linux Products GmbH
* Copyright (c) 2007, 2013 Tejun Heo <teheo@suse.de>
*
* This file is released under the GPLv2.
*/
#ifndef __KERNFS_INTERNAL_H
#define __KERNFS_INTERNAL_H
#include <linux/lockdep.h>
#include <linux/fs.h>
#include <linux/mutex.h>
#include <linux/xattr.h>
#include <linux/kernfs.h>
struct kernfs_iattrs {
struct iattr ia_iattr;
void *ia_secdata;
u32 ia_secdata_len;
struct simple_xattrs xattrs;
};
/* +1 to avoid triggering overflow warning when negating it */
#define KN_DEACTIVATED_BIAS (INT_MIN + 1)
/* KERNFS_TYPE_MASK and types are defined in include/linux/kernfs.h */
/**
* kernfs_root - find out the kernfs_root a kernfs_node belongs to
* @kn: kernfs_node of interest
*
* Return the kernfs_root @kn belongs to.
*/
static inline struct kernfs_root *kernfs_root(struct kernfs_node *kn)
{
/* if parent exists, it's always a dir; otherwise, @sd is a dir */
if (kn->parent)
kn = kn->parent;
return kn->dir.root;
}
/*
* mount.c
*/
struct kernfs_super_info {
struct super_block *sb;
/*
* The root associated with this super_block. Each super_block is
* identified by the root and ns it's associated with.
*/
struct kernfs_root *root;
/*
* Each sb is associated with one namespace tag, currently the
* network namespace of the task which mounted this kernfs
* instance. If multiple tags become necessary, make the following
* an array and compare kernfs_node tag against every entry.
*/
const void *ns;
/* anchored at kernfs_root->supers, protected by kernfs_mutex */
struct list_head node;
};
#define kernfs_info(SB) ((struct kernfs_super_info *)(SB->s_fs_info))
extern const struct super_operations kernfs_sops;
extern struct kmem_cache *kernfs_node_cache;
/*
* inode.c
*/
extern const struct xattr_handler *kernfs_xattr_handlers[];
void kernfs_evict_inode(struct inode *inode);
int kernfs_iop_permission(struct inode *inode, int mask);
int kernfs_iop_setattr(struct dentry *dentry, struct iattr *iattr);
int kernfs_iop_getattr(const struct path *path, struct kstat *stat,
u32 request_mask, unsigned int query_flags);
ssize_t kernfs_iop_listxattr(struct dentry *dentry, char *buf, size_t size);
/*
* dir.c
*/
extern struct mutex kernfs_mutex;
extern const struct dentry_operations kernfs_dops;
extern const struct file_operations kernfs_dir_fops;
extern const struct inode_operations kernfs_dir_iops;
struct kernfs_node *kernfs_get_active(struct kernfs_node *kn);
void kernfs_put_active(struct kernfs_node *kn);
int kernfs_add_one(struct kernfs_node *kn);
struct kernfs_node *kernfs_new_node(struct kernfs_node *parent,
const char *name, umode_t mode,
unsigned flags);
struct kernfs_node *kernfs_find_and_get_node_by_ino(struct kernfs_root *root,
unsigned int ino);
/*
* file.c
*/
extern const struct file_operations kernfs_file_fops;
void kernfs_drain_open_files(struct kernfs_node *kn);
/*
* symlink.c
*/
extern const struct inode_operations kernfs_symlink_iops;
#endif /* __KERNFS_INTERNAL_H */