/*
   * V9FS definitions.
   *
   *  Copyright (C) 2004-2008 by Eric Van Hensbergen <ericvh@gmail.com>
   *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
   *
   *  This program is free software; you can redistribute it and/or modify
   *  it under the terms of the GNU General Public License version 2
   *  as published by the Free Software Foundation.
   *
   *  This program is distributed in the hope that it will be useful,
   *  but WITHOUT ANY WARRANTY; without even the implied warranty of
   *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   *  GNU General Public License for more details.
   *
   *  You should have received a copy of the GNU General Public License
   *  along with this program; if not, write to:
   *  Free Software Foundation
   *  51 Franklin Street, Fifth Floor
   *  Boston, MA  02111-1301  USA
   *
   */
  #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,
  };
  
  /**
   * 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_cookie *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 backing_dev_info bdi;
  	struct rw_semaphore rename_sem;
  };
  
  /* cache_validity flags */
  #define V9FS_INO_INVALID_ATTR 0x01
  
  struct v9fs_inode {
  #ifdef CONFIG_9P_FSCACHE
  	spinlock_t fscache_lock;
  	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);
  }
  
  struct p9_fid *v9fs_session_init(struct v9fs_session_info *, const char *,
  									char *);
  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 inode *old_dir, struct dentry *old_dentry,
  			struct inode *new_dir, struct dentry *new_dentry);
  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