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/*

 * 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 */