/*

 * 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

#ifdef __KERNEL__

# 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 */