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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/config.h>
# 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.
 *  Possible future encodings:
 *     1  - 4 byte user specified identifier
 *
 * 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

#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 */
        umode_t                 fh_post_mode;   /* i_mode */
        nlink_t                 fh_post_nlink;  /* i_nlink */
        uid_t                   fh_post_uid;    /* i_uid */
        gid_t                   fh_post_gid;    /* i_gid */
        __u64                   fh_post_size;   /* i_size */
        unsigned long           fh_post_blocks; /* i_blocks */
        unsigned long           fh_post_blksize;/* i_blksize */
        __u32                   fh_post_rdev[2];/* i_rdev */
        struct timespec         fh_post_atime;  /* i_atime */
        struct timespec         fh_post_mtime;  /* i_mtime */
        struct timespec         fh_post_ctime;  /* i_ctime */
#endif /* CONFIG_NFSD_V3 */

} svc_fh;

static inline void mk_fsid_v0(u32 *fsidv, dev_t dev, ino_t ino)
{
        fsidv[0] = htonl((MAJOR(dev)<<16) |
                        MINOR(dev));
        fsidv[1] = ino_t_to_u32(ino);
}

static inline void mk_fsid_v1(u32 *fsidv, u32 fsid)
{
        fsidv[0] = fsid;
}

static inline void mk_fsid_v2(u32 *fsidv, dev_t dev, ino_t ino)
{
        fsidv[0] = htonl(MAJOR(dev));
        fsidv[1] = htonl(MINOR(dev));
        fsidv[2] = ino_t_to_u32(ino);
}

/*
 * Shorthand for dprintk()'s
 */
inline static char * SVCFH_fmt(struct svc_fh *fhp)
{
        struct knfsd_fh *fh = &fhp->fh_handle;
       
        static char buf[80];
        sprintf(buf, "%d: %08x %08x %08x %08x %08x %08x",
                fh->fh_size,
                fh->fh_base.fh_pad[0],
                fh->fh_base.fh_pad[1],
                fh->fh_base.fh_pad[2],
                fh->fh_base.fh_pad[3],
                fh->fh_base.fh_pad[4],
                fh->fh_base.fh_pad[5]);
        return buf;
}
/*
 * Function prototypes
 */
u32     fh_verify(struct svc_rqst *, struct svc_fh *, int, int);
int     fh_compose(struct svc_fh *, struct svc_export *, struct dentry *, struct svc_fh *);
int     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)
{
        if (src->fh_dentry || src->fh_locked) {
                struct dentry *dentry = src->fh_dentry;
                printk(KERN_ERR "fh_copy: copying %s/%s, already verified!\n",
                        dentry->d_parent->d_name.name, dentry->d_name.name);
        }
                       
        *dst = *src;
        return dst;
}

static __inline__ void
fh_dup2(struct svc_fh *dst, struct svc_fh *src)
{
        fh_put(dst);
        dget(src->fh_dentry);
        *dst = *src;
}

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;
        }
}

/*
 * Fill in the post_op attr for the wcc data
 */
static inline void
fill_post_wcc(struct svc_fh *fhp)
{
        struct inode    *inode = fhp->fh_dentry->d_inode;

        if (fhp->fh_post_saved)
                printk("nfsd: inode locked twice during operation.\n");

        fhp->fh_post_mode       = inode->i_mode;
        fhp->fh_post_nlink      = inode->i_nlink;
        fhp->fh_post_uid        = inode->i_uid;
        fhp->fh_post_gid        = inode->i_gid;
        fhp->fh_post_size       = inode->i_size;
        if (inode->i_blksize) {
                fhp->fh_post_blksize    = inode->i_blksize;
                fhp->fh_post_blocks     = inode->i_blocks;
        } else {
                fhp->fh_post_blksize    = BLOCK_SIZE;
                /* how much do we care for accuracy with MinixFS? */
                fhp->fh_post_blocks     = (inode->i_size+511) >> 9;
        }
        fhp->fh_post_rdev[0]    = htonl((u32)imajor(inode));
        fhp->fh_post_rdev[1]    = htonl((u32)iminor(inode));
        fhp->fh_post_atime      = inode->i_atime;
        fhp->fh_post_mtime      = inode->i_mtime;
        fhp->fh_post_ctime      = inode->i_ctime;
        fhp->fh_post_saved      = 1;
}
#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_sem's at once
 * so, any changes here should be reflected there.
 */
static inline void
fh_lock(struct svc_fh *fhp)
{
        struct dentry   *dentry = fhp->fh_dentry;
        struct inode    *inode;

        dfprintk(FILEOP, "nfsd: fh_lock(%s) locked = %d\n",
                        SVCFH_fmt(fhp), fhp->fh_locked);

        if (!fhp->fh_dentry) {
                printk(KERN_ERR "fh_lock: fh not verified!\n");
                return;
        }
        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;
        down(&inode->i_sem);
        fill_pre_wcc(fhp);
        fhp->fh_locked = 1;
}

/*
 * Unlock a file handle/inode
 */
static inline void
fh_unlock(struct svc_fh *fhp)
{
        if (!fhp->fh_dentry)
                printk(KERN_ERR "fh_unlock: fh not verified!\n");

        if (fhp->fh_locked) {
                fill_post_wcc(fhp);
                up(&fhp->fh_dentry->d_inode->i_sem);
                fhp->fh_locked = 0;
        }
}
#endif /* __KERNEL__ */


#endif /* _LINUX_NFSD_FH_H */