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linux/fs/configfs/configfs_internal.h
Christian Brauner 7a77db9551
fs: port ->symlink() to pass mnt_idmap 
Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2023-01-19 09:24:25 +01:00

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/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* configfs_internal.h - Internal stuff for configfs
*
* Based on sysfs:
* sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
*
* configfs Copyright (C) 2005 Oracle. All rights reserved.
*/
#ifdef pr_fmt
#undef pr_fmt
#endif
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/spinlock.h>
struct configfs_fragment {
atomic_t frag_count;
struct rw_semaphore frag_sem;
bool frag_dead;
};
void put_fragment(struct configfs_fragment *);
struct configfs_fragment *get_fragment(struct configfs_fragment *);
struct configfs_dirent {
atomic_t s_count;
int s_dependent_count;
struct list_head s_sibling;
struct list_head s_children;
int s_links;
void * s_element;
int s_type;
umode_t s_mode;
struct dentry * s_dentry;
struct iattr * s_iattr;
#ifdef CONFIG_LOCKDEP
int s_depth;
#endif
struct configfs_fragment *s_frag;
};
#define CONFIGFS_ROOT 0x0001
#define CONFIGFS_DIR 0x0002
#define CONFIGFS_ITEM_ATTR 0x0004
#define CONFIGFS_ITEM_BIN_ATTR 0x0008
#define CONFIGFS_ITEM_LINK 0x0020
#define CONFIGFS_USET_DIR 0x0040
#define CONFIGFS_USET_DEFAULT 0x0080
#define CONFIGFS_USET_DROPPING 0x0100
#define CONFIGFS_USET_IN_MKDIR 0x0200
#define CONFIGFS_USET_CREATING 0x0400
#define CONFIGFS_NOT_PINNED (CONFIGFS_ITEM_ATTR | CONFIGFS_ITEM_BIN_ATTR)
extern struct mutex configfs_symlink_mutex;
extern spinlock_t configfs_dirent_lock;
extern struct kmem_cache *configfs_dir_cachep;
extern int configfs_is_root(struct config_item *item);
extern struct inode * configfs_new_inode(umode_t mode, struct configfs_dirent *, struct super_block *);
extern struct inode *configfs_create(struct dentry *, umode_t mode);
extern int configfs_create_file(struct config_item *, const struct configfs_attribute *);
extern int configfs_create_bin_file(struct config_item *,
const struct configfs_bin_attribute *);
extern int configfs_make_dirent(struct configfs_dirent *, struct dentry *,
void *, umode_t, int, struct configfs_fragment *);
extern int configfs_dirent_is_ready(struct configfs_dirent *);
extern void configfs_hash_and_remove(struct dentry * dir, const char * name);
extern const unsigned char * configfs_get_name(struct configfs_dirent *sd);
extern void configfs_drop_dentry(struct configfs_dirent *sd, struct dentry *parent);
extern int configfs_setattr(struct mnt_idmap *idmap,
struct dentry *dentry, struct iattr *iattr);
extern struct dentry *configfs_pin_fs(void);
extern void configfs_release_fs(void);
extern const struct file_operations configfs_dir_operations;
extern const struct file_operations configfs_file_operations;
extern const struct file_operations configfs_bin_file_operations;
extern const struct inode_operations configfs_dir_inode_operations;
extern const struct inode_operations configfs_root_inode_operations;
extern const struct inode_operations configfs_symlink_inode_operations;
extern const struct dentry_operations configfs_dentry_ops;
extern int configfs_symlink(struct mnt_idmap *idmap,
struct inode *dir, struct dentry *dentry,
const char *symname);
extern int configfs_unlink(struct inode *dir, struct dentry *dentry);
int configfs_create_link(struct configfs_dirent *target, struct dentry *parent,
struct dentry *dentry, char *body);
static inline struct config_item * to_item(struct dentry * dentry)
{
struct configfs_dirent * sd = dentry->d_fsdata;
return ((struct config_item *) sd->s_element);
}
static inline struct configfs_attribute * to_attr(struct dentry * dentry)
{
struct configfs_dirent * sd = dentry->d_fsdata;
return ((struct configfs_attribute *) sd->s_element);
}
static inline struct configfs_bin_attribute *to_bin_attr(struct dentry *dentry)
{
struct configfs_attribute *attr = to_attr(dentry);
return container_of(attr, struct configfs_bin_attribute, cb_attr);
}
static inline struct config_item *configfs_get_config_item(struct dentry *dentry)
{
struct config_item * item = NULL;
spin_lock(&dentry->d_lock);
if (!d_unhashed(dentry)) {
struct configfs_dirent * sd = dentry->d_fsdata;
item = config_item_get(sd->s_element);
}
spin_unlock(&dentry->d_lock);
return item;
}
static inline void release_configfs_dirent(struct configfs_dirent * sd)
{
if (!(sd->s_type & CONFIGFS_ROOT)) {
kfree(sd->s_iattr);
put_fragment(sd->s_frag);
kmem_cache_free(configfs_dir_cachep, sd);
}
}
static inline struct configfs_dirent * configfs_get(struct configfs_dirent * sd)
{
if (sd) {
WARN_ON(!atomic_read(&sd->s_count));
atomic_inc(&sd->s_count);
}
return sd;
}
static inline void configfs_put(struct configfs_dirent * sd)
{
WARN_ON(!atomic_read(&sd->s_count));
if (atomic_dec_and_test(&sd->s_count))
release_configfs_dirent(sd);
}
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