/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * V9FS definitions.
 *
 *  Copyright (C) 2004-2008 by Eric Van Hensbergen <ericvh@gmail.com>
 *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
 */
#ifndef FS_9P_V9FS_H
#define FS_9P_V9FS_H

#include <linux/backing-dev.h>

/**
 * enum p9_session_flags - option flags for each 9P session
 * @V9FS_PROTO_2000U: whether or not to use 9P2000.u extensions
 * @V9FS_PROTO_2000L: whether or not to use 9P2000.l extensions
 * @V9FS_ACCESS_SINGLE: only the mounting user can access the hierarchy
 * @V9FS_ACCESS_USER: a new attach will be issued for every user (default)
 * @V9FS_ACCESS_CLIENT: Just like user, but access check is performed on client.
 * @V9FS_ACCESS_ANY: use a single attach for all users
 * @V9FS_ACCESS_MASK: bit mask of different ACCESS options
 * @V9FS_POSIX_ACL: POSIX ACLs are enforced
 *
 * Session flags reflect options selected by users at mount time
 */
#define	V9FS_ACCESS_ANY (V9FS_ACCESS_SINGLE | \
			 V9FS_ACCESS_USER |   \
			 V9FS_ACCESS_CLIENT)
#define V9FS_ACCESS_MASK V9FS_ACCESS_ANY
#define V9FS_ACL_MASK V9FS_POSIX_ACL

enum p9_session_flags {
	V9FS_PROTO_2000U	= 0x01,
	V9FS_PROTO_2000L	= 0x02,
	V9FS_ACCESS_SINGLE	= 0x04,
	V9FS_ACCESS_USER	= 0x08,
	V9FS_ACCESS_CLIENT	= 0x10,
	V9FS_POSIX_ACL		= 0x20
};

/* possible values of ->cache */
/**
 * enum p9_cache_modes - user specified cache preferences
 * @CACHE_NONE: do not cache data, dentries, or directory contents (default)
 * @CACHE_LOOSE: cache data, dentries, and directory contents w/no consistency
 *
 * eventually support loose, tight, time, session, default always none
 */

enum p9_cache_modes {
	CACHE_NONE,
	CACHE_MMAP,
	CACHE_LOOSE,
	CACHE_FSCACHE,
	nr__p9_cache_modes
};

/**
 * struct v9fs_session_info - per-instance session information
 * @flags: session options of type &p9_session_flags
 * @nodev: set to 1 to disable device mapping
 * @debug: debug level
 * @afid: authentication handle
 * @cache: cache mode of type &p9_cache_modes
 * @cachetag: the tag of the cache associated with this session
 * @fscache: session cookie associated with FS-Cache
 * @uname: string user name to mount hierarchy as
 * @aname: mount specifier for remote hierarchy
 * @maxdata: maximum data to be sent/recvd per protocol message
 * @dfltuid: default numeric userid to mount hierarchy as
 * @dfltgid: default numeric groupid to mount hierarchy as
 * @uid: if %V9FS_ACCESS_SINGLE, the numeric uid which mounted the hierarchy
 * @clnt: reference to 9P network client instantiated for this session
 * @slist: reference to list of registered 9p sessions
 *
 * This structure holds state for each session instance established during
 * a sys_mount() .
 *
 * Bugs: there seems to be a lot of state which could be condensed and/or
 * removed.
 */

struct v9fs_session_info {
	/* options */
	unsigned char flags;
	unsigned char nodev;
	unsigned short debug;
	unsigned int afid;
	unsigned int cache;
#ifdef CONFIG_9P_FSCACHE
	char *cachetag;
	struct fscache_volume *fscache;
#endif

	char *uname;		/* user name to mount as */
	char *aname;		/* name of remote hierarchy being mounted */
	unsigned int maxdata;	/* max data for client interface */
	kuid_t dfltuid;		/* default uid/muid for legacy support */
	kgid_t dfltgid;		/* default gid for legacy support */
	kuid_t uid;		/* if ACCESS_SINGLE, the uid that has access */
	struct p9_client *clnt;	/* 9p client */
	struct list_head slist; /* list of sessions registered with v9fs */
	struct rw_semaphore rename_sem;
	long session_lock_timeout; /* retry interval for blocking locks */
};

/* cache_validity flags */
#define V9FS_INO_INVALID_ATTR 0x01

struct v9fs_inode {
#ifdef CONFIG_9P_FSCACHE
	struct fscache_cookie *fscache;
#endif
	struct p9_qid qid;
	unsigned int cache_validity;
	struct p9_fid *writeback_fid;
	struct mutex v_mutex;
	struct inode vfs_inode;
};

static inline struct v9fs_inode *V9FS_I(const struct inode *inode)
{
	return container_of(inode, struct v9fs_inode, vfs_inode);
}

static inline struct fscache_cookie *v9fs_inode_cookie(struct v9fs_inode *v9inode)
{
#ifdef CONFIG_9P_FSCACHE
	return v9inode->fscache;
#else
	return NULL;
#endif
}

static inline struct fscache_volume *v9fs_session_cache(struct v9fs_session_info *v9ses)
{
#ifdef CONFIG_9P_FSCACHE
	return v9ses->fscache;
#else
	return NULL;
#endif
}


extern int v9fs_show_options(struct seq_file *m, struct dentry *root);

struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
				 const char *dev_name, char *data);
extern void v9fs_session_close(struct v9fs_session_info *v9ses);
extern void v9fs_session_cancel(struct v9fs_session_info *v9ses);
extern void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses);
extern struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
				      unsigned int flags);
extern int v9fs_vfs_unlink(struct inode *i, struct dentry *d);
extern int v9fs_vfs_rmdir(struct inode *i, struct dentry *d);
extern int v9fs_vfs_rename(struct user_namespace *mnt_userns,
			   struct inode *old_dir, struct dentry *old_dentry,
			   struct inode *new_dir, struct dentry *new_dentry,
			   unsigned int flags);
extern struct inode *v9fs_inode_from_fid(struct v9fs_session_info *v9ses,
					 struct p9_fid *fid,
					 struct super_block *sb, int new);
extern const struct inode_operations v9fs_dir_inode_operations_dotl;
extern const struct inode_operations v9fs_file_inode_operations_dotl;
extern const struct inode_operations v9fs_symlink_inode_operations_dotl;
extern struct inode *v9fs_inode_from_fid_dotl(struct v9fs_session_info *v9ses,
					      struct p9_fid *fid,
					      struct super_block *sb, int new);

/* other default globals */
#define V9FS_PORT	564
#define V9FS_DEFUSER	"nobody"
#define V9FS_DEFANAME	""
#define V9FS_DEFUID	KUIDT_INIT(-2)
#define V9FS_DEFGID	KGIDT_INIT(-2)

static inline struct v9fs_session_info *v9fs_inode2v9ses(struct inode *inode)
{
	return inode->i_sb->s_fs_info;
}

static inline struct v9fs_session_info *v9fs_dentry2v9ses(struct dentry *dentry)
{
	return dentry->d_sb->s_fs_info;
}

static inline int v9fs_proto_dotu(struct v9fs_session_info *v9ses)
{
	return v9ses->flags & V9FS_PROTO_2000U;
}

static inline int v9fs_proto_dotl(struct v9fs_session_info *v9ses)
{
	return v9ses->flags & V9FS_PROTO_2000L;
}

/**
 * v9fs_get_inode_from_fid - Helper routine to populate an inode by
 * issuing a attribute request
 * @v9ses: session information
 * @fid: fid to issue attribute request for
 * @sb: superblock on which to create inode
 *
 */
static inline struct inode *
v9fs_get_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
			struct super_block *sb)
{
	if (v9fs_proto_dotl(v9ses))
		return v9fs_inode_from_fid_dotl(v9ses, fid, sb, 0);
	else
		return v9fs_inode_from_fid(v9ses, fid, sb, 0);
}

/**
 * v9fs_get_new_inode_from_fid - Helper routine to populate an inode by
 * issuing a attribute request
 * @v9ses: session information
 * @fid: fid to issue attribute request for
 * @sb: superblock on which to create inode
 *
 */
static inline struct inode *
v9fs_get_new_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
			    struct super_block *sb)
{
	if (v9fs_proto_dotl(v9ses))
		return v9fs_inode_from_fid_dotl(v9ses, fid, sb, 1);
	else
		return v9fs_inode_from_fid(v9ses, fid, sb, 1);
}

#endif