text: /*
   * include/linux/nfsd/nfsfh.h
   *
   * This file describes the layout of the file handles as passed
   * over the wire.
   *
   * Earlier versions of knfsd used to sign file handles using keyed MD5
   * or SHA. I've removed this code, because it doesn't give you more
   * security than blocking external access to port 2049 on your firewall.
   *
   * Copyright (C) 1995, 1996, 1997 Olaf Kirch <okir@monad.swb.de>
   */
  
  #ifndef _LINUX_NFSD_FH_H
  #define _LINUX_NFSD_FH_H
  
  #include <asm/types.h>
  #ifdef __KERNEL__
  # include <linux/types.h>
  # include <linux/string.h>
  # include <linux/fs.h>
  #endif
  #include <linux/nfsd/const.h>
  #include <linux/nfsd/debug.h>
  
  /*
   * This is the old "dentry style" Linux NFSv2 file handle.
   *
   * The xino and xdev fields are currently used to transport the
   * ino/dev of the exported inode.
   */
  struct nfs_fhbase_old {
  	__u32		fb_dcookie;	/* dentry cookie - always 0xfeebbaca */
  	__u32		fb_ino;		/* our inode number */
  	__u32		fb_dirino;	/* dir inode number, 0 for directories */
  	__u32		fb_dev;		/* our device */
  	__u32		fb_xdev;
  	__u32		fb_xino;
  	__u32		fb_generation;
  };
  
  /*
   * This is the new flexible, extensible style NFSv2/v3 file handle.
   * by Neil Brown <neilb@cse.unsw.edu.au> - March 2000
   *
   * The file handle is seens as a list of 4byte words.
   * The first word contains a version number (1) and four descriptor bytes
   * that tell how the remaining 3 variable length fields should be handled.
   * These three bytes are auth_type, fsid_type and fileid_type.
   *
   * All 4byte values are in host-byte-order.
   *
   * The auth_type field specifies how the filehandle can be authenticated
   * This might allow a file to be confirmed to be in a writable part of a
   * filetree without checking the path from it upto the root.
   * Current values:
   *     0  - No authentication.  fb_auth is 0 bytes long
   * Possible future values:
   *     1  - 4 bytes taken from MD5 hash of the remainer of the file handle
   *          prefixed by a secret and with the important export flags.
   *
   * The fsid_type identifies how the filesystem (or export point) is
   *    encoded.
   *  Current values:
   *     0  - 4 byte device id (ms-2-bytes major, ls-2-bytes minor), 4byte inode number
   *        NOTE: we cannot use the kdev_t device id value, because kdev_t.h
   *              says we mustn't.  We must break it up and reassemble.
   *     1  - 4 byte user specified identifier
   *     2  - 4 byte major, 4 byte minor, 4 byte inode number - DEPRECATED
   *     3  - 4 byte device id, encoded for user-space, 4 byte inode number
   *
   * The fileid_type identified how the file within the filesystem is encoded.
   * This is (will be) passed to, and set by, the underlying filesystem if it supports
   * filehandle operations.  The filesystem must not use the value '0' or '0xff' and may
   * only use the values 1 and 2 as defined below:
   *  Current values:
   *    0   - The root, or export point, of the filesystem.  fb_fileid is 0 bytes.
   *    1   - 32bit inode number, 32 bit generation number.
   *    2   - 32bit inode number, 32 bit generation number, 32 bit parent directory inode number.
   *
   */
  struct nfs_fhbase_new {
  	__u8		fb_version;	/* == 1, even => nfs_fhbase_old */
  	__u8		fb_auth_type;
  	__u8		fb_fsid_type;
  	__u8		fb_fileid_type;
  	__u32		fb_auth[1];
  /*	__u32		fb_fsid[0]; floating */
  /*	__u32		fb_fileid[0]; floating */
  };
  
  struct knfsd_fh {
  	unsigned int	fh_size;	/* significant for NFSv3.
  					 * Points to the current size while building
  					 * a new file handle
  					 */
  	union {
  		struct nfs_fhbase_old	fh_old;
  		__u32			fh_pad[NFS4_FHSIZE/4];
  		struct nfs_fhbase_new	fh_new;
  	} fh_base;
  };
  
  #define ofh_dcookie		fh_base.fh_old.fb_dcookie
  #define ofh_ino			fh_base.fh_old.fb_ino
  #define ofh_dirino		fh_base.fh_old.fb_dirino
  #define ofh_dev			fh_base.fh_old.fb_dev
  #define ofh_xdev		fh_base.fh_old.fb_xdev
  #define ofh_xino		fh_base.fh_old.fb_xino
  #define ofh_generation		fh_base.fh_old.fb_generation
  
  #define	fh_version		fh_base.fh_new.fb_version
  #define	fh_fsid_type		fh_base.fh_new.fb_fsid_type
  #define	fh_auth_type		fh_base.fh_new.fb_auth_type
  #define	fh_fileid_type		fh_base.fh_new.fb_fileid_type
  #define	fh_auth			fh_base.fh_new.fb_auth
  #define	fh_fsid			fh_base.fh_new.fb_auth
  
  #ifdef __KERNEL__
  
  static inline __u32 ino_t_to_u32(ino_t ino)
  {
  	return (__u32) ino;
  }
  
  static inline ino_t u32_to_ino_t(__u32 uino)
  {
  	return (ino_t) uino;
  }
  
  /*
   * This is the internal representation of an NFS handle used in knfsd.
   * pre_mtime/post_version will be used to support wcc_attr's in NFSv3.
   */
  typedef struct svc_fh {
  	struct knfsd_fh		fh_handle;	/* FH data */
  	struct dentry *		fh_dentry;	/* validated dentry */
  	struct svc_export *	fh_export;	/* export pointer */
  	int			fh_maxsize;	/* max size for fh_handle */
  
  	unsigned char		fh_locked;	/* inode locked by us */
  
  #ifdef CONFIG_NFSD_V3
  	unsigned char		fh_post_saved;	/* post-op attrs saved */
  	unsigned char		fh_pre_saved;	/* pre-op attrs saved */
  
  	/* Pre-op attributes saved during fh_lock */
  	__u64			fh_pre_size;	/* size before operation */
  	struct timespec		fh_pre_mtime;	/* mtime before oper */
  	struct timespec		fh_pre_ctime;	/* ctime before oper */
  
  	/* Post-op attributes saved in fh_unlock */
  	struct kstat		fh_post_attr;	/* full attrs after operation */
  #endif /* CONFIG_NFSD_V3 */
  
  } svc_fh;
  
  enum nfsd_fsid {
  	FSID_DEV = 0,
  	FSID_NUM,
  	FSID_MAJOR_MINOR,
  	FSID_ENCODE_DEV,
  	FSID_UUID4_INUM,
  	FSID_UUID8,
  	FSID_UUID16,
  	FSID_UUID16_INUM,
  };
  
  enum fsid_source {
  	FSIDSOURCE_DEV,
  	FSIDSOURCE_FSID,
  	FSIDSOURCE_UUID,
  };
  extern enum fsid_source fsid_source(struct svc_fh *fhp);
  
  
  /* This might look a little large to "inline" but in all calls except
   * one, 'vers' is constant so moste of the function disappears.
   */
  static inline void mk_fsid(int vers, u32 *fsidv, dev_t dev, ino_t ino,
  			   u32 fsid, unsigned char *uuid)
  {
  	u32 *up;
  	switch(vers) {
  	case FSID_DEV:
  		fsidv[0] = htonl((MAJOR(dev)<<16) |
  				 MINOR(dev));
  		fsidv[1] = ino_t_to_u32(ino);
  		break;
  	case FSID_NUM:
  		fsidv[0] = fsid;
  		break;
  	case FSID_MAJOR_MINOR:
  		fsidv[0] = htonl(MAJOR(dev));
  		fsidv[1] = htonl(MINOR(dev));
  		fsidv[2] = ino_t_to_u32(ino);
  		break;
  
  	case FSID_ENCODE_DEV:
  		fsidv[0] = new_encode_dev(dev);
  		fsidv[1] = ino_t_to_u32(ino);
  		break;
  
  	case FSID_UUID4_INUM:
  		/* 4 byte fsid and inode number */
  		up = (u32*)uuid;
  		fsidv[0] = ino_t_to_u32(ino);
  		fsidv[1] = up[0] ^ up[1] ^ up[2] ^ up[3];
  		break;
  
  	case FSID_UUID8:
  		/* 8 byte fsid  */
  		up = (u32*)uuid;
  		fsidv[0] = up[0] ^ up[2];
  		fsidv[1] = up[1] ^ up[3];
  		break;
  
  	case FSID_UUID16:
  		/* 16 byte fsid - NFSv3+ only */
  		memcpy(fsidv, uuid, 16);
  		break;
  
  	case FSID_UUID16_INUM:
  		/* 8 byte inode and 16 byte fsid */
  		*(u64*)fsidv = (u64)ino;
  		memcpy(fsidv+2, uuid, 16);
  		break;
  	default: BUG();
  	}
  }
  
  static inline int key_len(int type)
  {
  	switch(type) {
  	case FSID_DEV:		return 8;
  	case FSID_NUM: 		return 4;
  	case FSID_MAJOR_MINOR:	return 12;
  	case FSID_ENCODE_DEV:	return 8;
  	case FSID_UUID4_INUM:	return 8;
  	case FSID_UUID8:	return 8;
  	case FSID_UUID16:	return 16;
  	case FSID_UUID16_INUM:	return 24;
  	default: return 0;
  	}
  }
  
  /*
   * Shorthand for dprintk()'s
   */
  extern char * SVCFH_fmt(struct svc_fh *fhp);
  
  /*
   * Function prototypes
   */
  __be32	fh_verify(struct svc_rqst *, struct svc_fh *, int, int);
  __be32	fh_compose(struct svc_fh *, struct svc_export *, struct dentry *, struct svc_fh *);
  __be32	fh_update(struct svc_fh *);
  void	fh_put(struct svc_fh *);
  
  static __inline__ struct svc_fh *
  fh_copy(struct svc_fh *dst, struct svc_fh *src)
  {
  	WARN_ON(src->fh_dentry || src->fh_locked);
  			
  	*dst = *src;
  	return dst;
  }
  
  static __inline__ struct svc_fh *
  fh_init(struct svc_fh *fhp, int maxsize)
  {
  	memset(fhp, 0, sizeof(*fhp));
  	fhp->fh_maxsize = maxsize;
  	return fhp;
  }
  
  #ifdef CONFIG_NFSD_V3
  /*
   * Fill in the pre_op attr for the wcc data
   */
  static inline void
  fill_pre_wcc(struct svc_fh *fhp)
  {
  	struct inode    *inode;
  
  	inode = fhp->fh_dentry->d_inode;
  	if (!fhp->fh_pre_saved) {
  		fhp->fh_pre_mtime = inode->i_mtime;
  		fhp->fh_pre_ctime = inode->i_ctime;
  		fhp->fh_pre_size  = inode->i_size;
  		fhp->fh_pre_saved = 1;
  	}
  }
  
  extern void fill_post_wcc(struct svc_fh *);
  #else
  #define	fill_pre_wcc(ignored)
  #define fill_post_wcc(notused)
  #endif /* CONFIG_NFSD_V3 */
  
  
  /*
   * Lock a file handle/inode
   * NOTE: both fh_lock and fh_unlock are done "by hand" in
   * vfs.c:nfsd_rename as it needs to grab 2 i_mutex's at once
   * so, any changes here should be reflected there.
   */
  
  static inline void
  fh_lock_nested(struct svc_fh *fhp, unsigned int subclass)
  {
  	struct dentry	*dentry = fhp->fh_dentry;
  	struct inode	*inode;
  
  	dfprintk(FILEOP, "nfsd: fh_lock(%s) locked = %d\n",
  			SVCFH_fmt(fhp), fhp->fh_locked);
  
  	BUG_ON(!dentry);
  
  	if (fhp->fh_locked) {
  		printk(KERN_WARNING "fh_lock: %s/%s already locked!\n",
  			dentry->d_parent->d_name.name, dentry->d_name.name);
  		return;
  	}
  
  	inode = dentry->d_inode;
  	mutex_lock_nested(&inode->i_mutex, subclass);
  	fill_pre_wcc(fhp);
  	fhp->fh_locked = 1;
  }
  
  static inline void
  fh_lock(struct svc_fh *fhp)
  {
  	fh_lock_nested(fhp, I_MUTEX_NORMAL);
  }
  
  /*
   * Unlock a file handle/inode
   */
  static inline void
  fh_unlock(struct svc_fh *fhp)
  {
  	BUG_ON(!fhp->fh_dentry);
  
  	if (fhp->fh_locked) {
  		fill_post_wcc(fhp);
  		mutex_unlock(&fhp->fh_dentry->d_inode->i_mutex);
  		fhp->fh_locked = 0;
  	}
  }
  #endif /* __KERNEL__ */
  
  
  #endif /* _LINUX_NFSD_FH_H */
  