Linux-2.4.0-test2

[davej-history.git] / fs / nfsd / nfsfh.c

/*
 * linux/fs/nfsd/nfsfh.c
 *
 * NFS server file handle treatment.
 *
 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
 * Portions Copyright (C) 1999 G. Allen Morris III <gam3@acm.org>
 * Extensive rewrite by Neil Brown <neilb@cse.unsw.edu.au> Southern-Spring 1999
 */

#include <linux/config.h>
#include <linux/sched.h>
#include <linux/malloc.h>
#include <linux/fs.h>
#include <linux/unistd.h>
#include <linux/string.h>
#include <linux/stat.h>
#include <linux/dcache.h>
#include <asm/pgtable.h>

#include <linux/sunrpc/svc.h>
#include <linux/nfsd/nfsd.h>

#define NFSDDBG_FACILITY                NFSDDBG_FH
#define NFSD_PARANOIA 1
/* #define NFSD_DEBUG_VERBOSE 1 */


static int nfsd_nr_verified = 0;
static int nfsd_nr_put = 0;


struct nfsd_getdents_callback {
        struct qstr *name;      /* name that was found. name->name already points to a buffer */
        unsigned long ino;      /* the inum we are looking for */
        int found;              /* inode matched? */
        int sequence;           /* sequence counter */
};

/*
 * A rather strange filldir function to capture
 * the name matching the specified inode number.
 */
static int filldir_one(void * __buf, const char * name, int len,
                        off_t pos, ino_t ino)
{
        struct nfsd_getdents_callback *buf = __buf;
        struct qstr *qs = buf->name;
        char *nbuf = (char*)qs->name; /* cast is to get rid of "const" */
        int result = 0;

        buf->sequence++;
#ifdef NFSD_DEBUG_VERBOSE
dprintk("filldir_one: seq=%d, ino=%ld, name=%s\n", buf->sequence, ino, name);
#endif
        if (buf->ino == ino) {
                qs->len = len;
                memcpy(nbuf, name, len);
                nbuf[len] = '\0';
                buf->found = 1;
                result = -1;
        }
        return result;
}

/*
 * Read a directory and return the name of the specified entry.
 * i_sem is already down().
 * The whole thing is a total BS. It should not be done via readdir(), damnit!
 * Oh, well, as soon as it will be in filesystems...
 */
static int get_ino_name(struct dentry *dentry, struct qstr *name, unsigned long ino)
{
        struct inode *dir = dentry->d_inode;
        int error;
        struct file file;
        struct nfsd_getdents_callback buffer;

        error = -ENOTDIR;
        if (!dir || !S_ISDIR(dir->i_mode))
                goto out;
        error = -EINVAL;
        if (!dir->i_fop)
                goto out;
        /*
         * Open the directory ...
         */
        error = init_private_file(&file, dentry, FMODE_READ);
        if (error)
                goto out;
        error = -EINVAL;
        if (!file.f_op->readdir)
                goto out_close;

        buffer.name = name;
        buffer.ino = ino;
        buffer.found = 0;
        buffer.sequence = 0;
        while (1) {
                int old_seq = buffer.sequence;
                error = file.f_op->readdir(&file, &buffer, filldir_one);
                if (error < 0)
                        break;

                error = 0;
                if (buffer.found)
                        break;
                error = -ENOENT;
                if (old_seq == buffer.sequence)
                        break;
        }

out_close:
        if (file.f_op->release)
                file.f_op->release(dir, &file);
out:
        return error;
}

/* this should be provided by each filesystem in an nfsd_operations interface as
 * iget isn't really the right interface
 */
static struct dentry *nfsd_iget(struct super_block *sb, unsigned long ino, __u32 generation)
{

        /* iget isn't really right if the inode is currently unallocated!!
         * This should really all be done inside each filesystem
         *
         * ext2fs' read_inode has been strengthed to return a bad_inode if the inode
         *   had been deleted.
         *
         * Currently we don't know the generation for parent directory, so a generation
         * of 0 means "accept any"
         */
        struct inode *inode;
        struct list_head *lp;
        struct dentry *result;
        inode = iget(sb, ino);
        if (is_bad_inode(inode)
            || (generation && inode->i_generation != generation)
                ) {
                /* we didn't find the right inode.. */
                dprintk("fh_verify: Inode %lu, Bad count: %d %d or version  %u %u\n",
                        inode->i_ino,
                        inode->i_nlink, atomic_read(&inode->i_count),
                        inode->i_generation,
                        generation);

                iput(inode);
                return ERR_PTR(-ESTALE);
        }
        /* now to find a dentry.
         * If possible, get a well-connected one
         */
        for (lp = inode->i_dentry.next; lp != &inode->i_dentry ; lp=lp->next) {
                result = list_entry(lp,struct dentry, d_alias);
                if (! (result->d_flags & DCACHE_NFSD_DISCONNECTED)) {
                        dget(result);
                        iput(inode);
                        return result;
                }
        }
        result = d_alloc_root(inode);
        if (result == NULL) {
                iput(inode);
                return ERR_PTR(-ENOMEM);
        }
        result->d_flags |= DCACHE_NFSD_DISCONNECTED;
        d_rehash(result); /* so a dput won't loose it */
        return result;
}

/* this routine links an IS_ROOT dentry into the dcache tree.  It gains "parent"
 * as a parent and "name" as a name
 * It should possibly go in dcache.c
 */
int d_splice(struct dentry *target, struct dentry *parent, struct qstr *name)
{
        struct dentry *tdentry;
#ifdef NFSD_PARANOIA
        if (!IS_ROOT(target))
                printk("nfsd: d_splice with no-root target: %s/%s\n", parent->d_name.name, name->name);
        if (!(target->d_flags & DCACHE_NFSD_DISCONNECTED))
                printk("nfsd: d_splice with non-DISCONNECTED target: %s/%s\n", parent->d_name.name, name->name);
#endif
        name->hash = full_name_hash(name->name, name->len);
        tdentry = d_alloc(parent, name);
        if (tdentry == NULL)
                return -ENOMEM;
        d_move(target, tdentry);

        /* tdentry will have been made a "child" of target (the parent of target)
         * make it an IS_ROOT instead
         */
        list_del(&tdentry->d_child);
        tdentry->d_parent = tdentry;
        d_rehash(target);
        dput(tdentry);

        /* if parent is properly connected, then we can assert that
         * the children are connected, but it must be a singluar (non-forking)
         * branch
         */
        if (!(parent->d_flags & DCACHE_NFSD_DISCONNECTED)) {
                while (target) {
                        target->d_flags &= ~DCACHE_NFSD_DISCONNECTED;
                        parent = target;
                        if (list_empty(&parent->d_subdirs))
                                target = NULL;
                        else {
                                target = list_entry(parent->d_subdirs.next, struct dentry, d_child);
#ifdef NFSD_PARANOIA
                                /* must be only child */
                                if (target->d_child.next != &parent->d_subdirs
                                    || target->d_child.prev != &parent->d_subdirs)
                                        printk("nfsd: d_splice found non-singular disconnected branch: %s/%s\n",
                                               parent->d_name.name, target->d_name.name);
#endif
                        }
                }
        }
        return 0;
}

/* this routine finds the dentry of the parent of a given directory
 * it should be in the filesystem accessed by nfsd_operations
 * it assumes lookup("..") works.
 */
struct dentry *nfsd_findparent(struct dentry *child)
{
        struct dentry *tdentry, *pdentry;
        tdentry = d_alloc(child, &(const struct qstr) {"..", 2, 0});
        if (!tdentry)
                return ERR_PTR(-ENOMEM);

        /* I'm going to assume that if the returned dentry is different, then
         * it is well connected.  But nobody returns different dentrys do they?
         */
        pdentry = child->d_inode->i_op->lookup(child->d_inode, tdentry);
        d_drop(tdentry); /* we never want ".." hashed */
        if (!pdentry) {
                /* I don't want to return a ".." dentry.
                 * I would prefer to return an unconnected "IS_ROOT" dentry,
                 * though a properly connected dentry is even better
                 */
                /* if first or last of alias list is not tdentry, use that
                 * else make a root dentry
                 */
                struct list_head *aliases = &tdentry->d_inode->i_dentry;
                if (aliases->next != aliases) {
                        pdentry = list_entry(aliases->next, struct dentry, d_alias);
                        if (pdentry == tdentry)
                                pdentry = list_entry(aliases->prev, struct dentry, d_alias);
                        if (pdentry == tdentry)
                                pdentry = NULL;
                        if (pdentry) dget(pdentry);
                }
                if (pdentry == NULL) {
                        pdentry = d_alloc_root(igrab(tdentry->d_inode));
                        if (pdentry) {
                                pdentry->d_flags |= DCACHE_NFSD_DISCONNECTED;
                                d_rehash(pdentry);
                        }
                }
                if (pdentry == NULL)
                        pdentry = ERR_PTR(-ENOMEM);
        }
        dput(tdentry); /* it is not hashed, it will be discarded */
        return pdentry;
}

static struct dentry *splice(struct dentry *child, struct dentry *parent)
{
        int err = 0;
        struct qstr qs;
        char namebuf[256];
        struct list_head *lp;
        struct dentry *tmp;
        /* child is an IS_ROOT (anonymous) dentry, but it is hypothesised that
         * it should be a child of parent.
         * We see if we can find a name and, if we can - splice it in.
         * We hold the i_sem on the parent the whole time to try to follow locking protocols.
         */
        qs.name = namebuf;
        down(&parent->d_inode->i_sem);

        /* Now, things might have changed while we waited.
         * Possibly a friendly filesystem found child and spliced it in in response
         * to a lookup (though nobody does this yet).  In this case, just succeed.
         */
        if (child->d_parent == parent) goto out;
        /* Possibly a new dentry has been made for this child->d_inode in parent by
         * a lookup.  In this case return that dentry. caller must notice and act accordingly
         */
        for (lp = child->d_inode->i_dentry.next; lp != &child->d_inode->i_dentry ; lp=lp->next) {
                tmp = list_entry(lp,struct dentry, d_alias);
                if (tmp->d_parent == parent) {
                        child = dget(tmp);
                        goto out;
                }
        }
        /* well, if we can find a name for child in parent, it should be safe to splice it in */
        err = get_ino_name(parent, &qs, child->d_inode->i_ino);
        if (err)
                goto out;
        tmp = d_lookup(parent, &qs);
        if (tmp) {
                /* Now that IS odd.  I wonder what it means... */
                err = -EEXIST;
                printk("nfsd-fh: found a name that I didn't expect: %s/%s\n", parent->d_name.name, qs.name);
                dput(tmp);
                goto out;
        }
        err = d_splice(child, parent, &qs);
        dprintk("nfsd_fh: found name %s for ino %ld\n", child->d_name.name, child->d_inode->i_ino);
 out:
        up(&parent->d_inode->i_sem);
        if (err)
                return ERR_PTR(err);
        else
                return child;
}

/*
 * This is the basic lookup mechanism for turning an NFS file handle
 * into a dentry.
 * We use nfsd_iget and if that doesn't return a suitably connected dentry,
 * we try to find the parent, and the parent of that and so-on until a
 * connection if made.
 */
static struct dentry *
find_fh_dentry(struct super_block *sb, ino_t ino, int generation, ino_t dirino, int needpath)
{
        struct dentry *dentry, *result = NULL;
        struct dentry *tmp;
        int  found =0;
        int err;
        /* the sb->s_nfsd_free_path_sem semaphore is needed to make sure that only one unconnected (free)
         * dcache path ever exists, as otherwise two partial paths might get
         * joined together, which would be very confusing.
         * If there is ever an unconnected non-root directory, then this lock
         * must be held.
         */


        nfsdstats.fh_lookup++;
        /*
         * Attempt to find the inode.
         */
 retry:
        result = nfsd_iget(sb, ino, generation);
        err = PTR_ERR(result);
        if (IS_ERR(result))
                goto err_out;
        err = -ESTALE;
        if (! (result->d_flags & DCACHE_NFSD_DISCONNECTED))
                return result;

        /* result is now an anonymous dentry, which may be adequate as it stands, or else
         * will get spliced into the dcache tree */

        if (!S_ISDIR(result->d_inode->i_mode) && ! needpath) {
                nfsdstats.fh_anon++;
                return result;
        }

        /* It's a directory, or we are required to confirm the file's
         * location in the tree.
         */
        dprintk("nfs_fh: need to look harder for %d/%ld\n",sb->s_dev,ino);
        down(&sb->s_nfsd_free_path_sem);

        /* claiming the semaphore might have allowed things to get fixed up */
        if (! (result->d_flags & DCACHE_NFSD_DISCONNECTED)) {
                up(&sb->s_nfsd_free_path_sem);
                return result;
        }


        found = 0;
        if (!S_ISDIR(result->d_inode->i_mode)) {
                nfsdstats.fh_nocache_nondir++;
                if (dirino == 0)
                        goto err_result; /* don't know how to find parent */
                else {
                        /* need to iget dirino and make sure this inode is in that directory */
                        dentry = nfsd_iget(sb, dirino, 0);
                        err = PTR_ERR(dentry);
                        if (IS_ERR(dentry))
                                goto err_result;
                        err = -ESTALE;
                        if (!dentry->d_inode
                            || !S_ISDIR(dentry->d_inode->i_mode)) {
                                goto err_dentry;
                        }
                        if ((!dentry->d_flags & DCACHE_NFSD_DISCONNECTED))
                                found = 1;
                        tmp = splice(result, dentry);
                        err = PTR_ERR(tmp);
                        if (IS_ERR(tmp))
                                goto err_dentry;
                        if (tmp != result) {
                                /* it is safe to just use tmp instead, but we must discard result first */
                                d_drop(result);
                                dput(result);
                                result = tmp;
                                /* If !found, then this is really wierd, but it shouldn't hurt */
                        }
                }
        } else {
                nfsdstats.fh_nocache_dir++;
                dentry = dget(result);
        }

        while(!found) {
                /* LOOP INVARIANT */
                /* haven't found a place in the tree yet, but we do have a free path
                 * from dentry down to result, and dentry is a directory.
                 * Have a hold on dentry and result */
                struct dentry *pdentry;
                struct inode *parent;

                pdentry = nfsd_findparent(dentry);
                err = PTR_ERR(pdentry);
                if (IS_ERR(pdentry))
                        goto err_dentry;
                parent = pdentry->d_inode;
                err = -EACCES;
                if (!parent) {
                        dput(pdentry);
                        goto err_dentry;
                }

                if (!(dentry->d_flags & DCACHE_NFSD_DISCONNECTED))
                        found = 1;

                tmp = splice(dentry, pdentry);
                if (tmp != dentry) {
                        /* Something wrong.  We need to drop thw whole dentry->result path
                         * whatever it was
                         */
                        struct dentry *d;
                        for (d=result ; d ; d=(d->d_parent == d)?NULL:d->d_parent)
                                d_drop(d);
                }
                if (IS_ERR(tmp)) {
                        err = PTR_ERR(tmp);
                        dput(pdentry);
                        goto err_dentry;
                }
                if (tmp != dentry) {
                        /* we lost a race,  try again
                         */
                        dput(tmp);
                        dput(dentry);
                        dput(result);   /* this will discard the whole free path, so we can up the semaphore */
                        up(&sb->s_nfsd_free_path_sem);
                        goto retry;
                }
                dput(dentry);
                dentry = pdentry;
        }
        dput(dentry);
        up(&sb->s_nfsd_free_path_sem);
        return result;

err_dentry:
        dput(dentry);
err_result:
        dput(result);
        up(&sb->s_nfsd_free_path_sem);
err_out:
        if (err == -ESTALE)
                nfsdstats.fh_stale++;
        return ERR_PTR(err);
}

/*
 * Perform sanity checks on the dentry in a client's file handle.
 *
 * Note that the file handle dentry may need to be freed even after
 * an error return.
 *
 * This is only called at the start of an nfsproc call, so fhp points to
 * a svc_fh which is all 0 except for the over-the-wire file handle.
 */
u32
fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
{
        struct knfsd_fh *fh = &fhp->fh_handle;
        struct svc_export *exp;
        struct dentry   *dentry;
        struct inode    *inode;
        u32             error = 0;

        dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp));

        if (!fhp->fh_dverified) {
                kdev_t xdev;
                ino_t xino;
                __u32 *datap=NULL;
                int data_left = fh->fh_size/4;
                int nfsdev;
                error = nfserr_stale;
#if CONFIG_NFSD_V3              
                if (rqstp->rq_vers == 3)
                        error = nfserr_badhandle;
#endif
                if (fh->fh_version == 1) {
                        
                        datap = fh->fh_auth;
                        if (--data_left<0) goto out;
                        switch (fh->fh_auth_type) {
                        case 0: break;
                        default: goto out;
                        }

                        switch (fh->fh_fsid_type) {
                        case 0:
                                if ((data_left-=2)<0) goto out;
                                nfsdev = ntohl(*datap++);
                                xdev = MKDEV(nfsdev>>16, nfsdev&0xFFFF);
                                xino = *datap++;
                                break;
                        default:
                                goto out;
                        }
                } else {
                        if (fh->fh_size != NFS_FHSIZE)
                                goto out;
                        /* assume old filehandle format */
                        xdev = u32_to_kdev_t(fh->ofh_xdev);
                        xino = u32_to_ino_t(fh->ofh_xino);
                }

                /*
                 * Look up the export entry.
                 */
                error = nfserr_stale; 
                exp = exp_get(rqstp->rq_client, xdev, xino);

                if (!exp) {
                        /* export entry revoked */
                        nfsdstats.fh_stale++;
                        goto out;
                }

                /* Check if the request originated from a secure port. */
                error = nfserr_perm;
                if (!rqstp->rq_secure && EX_SECURE(exp)) {
                        printk(KERN_WARNING
                               "nfsd: request from insecure port (%08x:%d)!\n",
                               ntohl(rqstp->rq_addr.sin_addr.s_addr),
                               ntohs(rqstp->rq_addr.sin_port));
                        goto out;
                }

                /* Set user creds if we haven't done so already. */
                nfsd_setuser(rqstp, exp);

                /*
                 * Look up the dentry using the NFS file handle.
                 */
                error = nfserr_stale;
#if CONFIG_NFSD_V3              
                if (rqstp->rq_vers == 3)
                        error = nfserr_badhandle;
#endif

                if (fh->fh_version == 1) {
                        /* if fileid_type != 0, and super_operations provide fh_to_dentry lookup,
                         *  then should use that */
                        switch (fh->fh_fileid_type) {
                        case 0:
                                dentry = dget(exp->ex_dentry);
                                break;
                        case 1:
                                if ((data_left-=2)<0) goto out;
                                dentry = find_fh_dentry(exp->ex_dentry->d_inode->i_sb,
                                                        datap[0], datap[1],
                                                        0,
                                                        !(exp->ex_flags & NFSEXP_NOSUBTREECHECK));
                                break;
                        case 2:
                                if ((data_left-=3)<0) goto out;
                                dentry = find_fh_dentry(exp->ex_dentry->d_inode->i_sb,
                                                        datap[0], datap[1],
                                                        datap[2],
                                                        !(exp->ex_flags & NFSEXP_NOSUBTREECHECK));
                                break;
                        default: goto out;
                        }
                } else {

                        dentry = find_fh_dentry(exp->ex_dentry->d_inode->i_sb,
                                                fh->ofh_ino, fh->ofh_generation,
                                                fh->ofh_dirino,
                                                !(exp->ex_flags & NFSEXP_NOSUBTREECHECK));
                }
                if (IS_ERR(dentry)) {
                        error = nfserrno(PTR_ERR(dentry));
                        goto out;
                }
#ifdef NFSD_PARANOIA
                if (S_ISDIR(dentry->d_inode->i_mode) &&
                    (dentry->d_flags & DCACHE_NFSD_DISCONNECTED)) {
                        printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %s/%s\n",
                               dentry->d_parent->d_name.name, dentry->d_name.name);
                }
#endif

                fhp->fh_dentry = dentry;
                fhp->fh_export = exp;
                fhp->fh_dverified = 1;
                nfsd_nr_verified++;
        } else {
                /* just rechecking permissions
                 * (e.g. nfsproc_create calls fh_verify, then nfsd_create does as well)
                 */
                dprintk("nfsd: fh_verify - just checking\n");
                dentry = fhp->fh_dentry;
                exp = fhp->fh_export;
        }

        inode = dentry->d_inode;

        /* Type check. The correct error return for type mismatches
         * does not seem to be generally agreed upon. SunOS seems to
         * use EISDIR if file isn't S_IFREG; a comment in the NFSv3
         * spec says this is incorrect (implementation notes for the
         * write call).
         */

        /* When is type ever negative? */
        if (type > 0 && (inode->i_mode & S_IFMT) != type) {
                error = (type == S_IFDIR)? nfserr_notdir : nfserr_isdir;
                goto out;
        }
        if (type < 0 && (inode->i_mode & S_IFMT) == -type) {
                error = (type == -S_IFDIR)? nfserr_notdir : nfserr_isdir;
                goto out;
        }

        /*
         * Security: Check that the export is valid for dentry <gam3@acm.org>
         */
        error = 0;

        if (!(exp->ex_flags & NFSEXP_NOSUBTREECHECK)) {
                if (exp->ex_dentry != dentry) {
                        struct dentry *tdentry = dentry;

                        do {
                                tdentry = tdentry->d_parent;
                                if (exp->ex_dentry == tdentry)
                                        break;
                                /* executable only by root and we can't be root */
                                if (current->fsuid
                                    && (exp->ex_flags & NFSEXP_ROOTSQUASH)
                                    && !(tdentry->d_inode->i_uid
                                         && (tdentry->d_inode->i_mode & S_IXUSR))
                                    && !(tdentry->d_inode->i_gid
                                         && (tdentry->d_inode->i_mode & S_IXGRP))
                                    && !(tdentry->d_inode->i_mode & S_IXOTH)
                                        ) {
                                        error = nfserr_stale;
                                        nfsdstats.fh_stale++;
                                        dprintk("fh_verify: no root_squashed access.\n");
                                }
                        } while ((tdentry != tdentry->d_parent));
                        if (exp->ex_dentry != tdentry) {
                                error = nfserr_stale;
                                nfsdstats.fh_stale++;
                                printk("nfsd Security: %s/%s bad export.\n",
                                       dentry->d_parent->d_name.name,
                                       dentry->d_name.name);
                                goto out;
                        }
                }
        }

        /* Finally, check access permissions. */
        if (!error) {
                error = nfsd_permission(exp, dentry, access);
        }
#ifdef NFSD_PARANOIA
        if (error) {
                printk("fh_verify: %s/%s permission failure, acc=%x, error=%d\n",
                       dentry->d_parent->d_name.name, dentry->d_name.name, access, (error >> 24));
        }
#endif
out:
        return error;
}

/*
 * Compose a file handle for an NFS reply.
 *
 * Note that when first composed, the dentry may not yet have
 * an inode.  In this case a call to fh_update should be made
 * before the fh goes out on the wire ...
 */
inline int _fh_update(struct dentry *dentry, struct svc_export *exp,
                      __u32 **datapp, int maxsize)
{
        __u32 *datap= *datapp;
        if (dentry == exp->ex_dentry)
                return 0;
        /* if super_operations provides dentry_to_fh lookup, should use that */
        
        *datap++ = ino_t_to_u32(dentry->d_inode->i_ino);
        *datap++ = dentry->d_inode->i_generation;
        if (S_ISDIR(dentry->d_inode->i_mode) || (exp->ex_flags & NFSEXP_NOSUBTREECHECK)){
                *datapp = datap;
                return 1;
        }
        *datap++ = ino_t_to_u32(dentry->d_parent->d_inode->i_ino);
        *datapp = datap;
        return 2;
}

int
fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry)
{
        struct inode * inode = dentry->d_inode;
        struct dentry *parent = dentry->d_parent;
        __u32 *datap;

        dprintk("nfsd: fh_compose(exp %x/%ld %s/%s, ino=%ld)\n",
                exp->ex_dev, (long) exp->ex_ino,
                parent->d_name.name, dentry->d_name.name,
                (inode ? inode->i_ino : 0));

        if (fhp->fh_dverified || fhp->fh_locked || fhp->fh_dentry) {
                printk(KERN_ERR "fh_compose: fh %s/%s not initialized!\n",
                        parent->d_name.name, dentry->d_name.name);
        }
        if (fhp->fh_maxsize < NFS_FHSIZE)
                printk(KERN_ERR "fh_compose: called with maxsize %d! %s/%s\n",
                       fhp->fh_maxsize, parent->d_name.name, dentry->d_name.name);

        fhp->fh_dentry = dentry; /* our internal copy */
        fhp->fh_export = exp;

        fhp->fh_handle.fh_version = 1;
        fhp->fh_handle.fh_auth_type = 0;
        fhp->fh_handle.fh_fsid_type = 0;
        datap = fhp->fh_handle.fh_auth+0;
        /* fsid_type 0 == 2byte major, 2byte minor, 4byte inode */
        *datap++ = htonl((MAJOR(exp->ex_dev)<<16)| MINOR(exp->ex_dev));
        *datap++ = ino_t_to_u32(exp->ex_ino);

        if (inode)
                fhp->fh_handle.fh_fileid_type =
                        _fh_update(dentry, exp, &datap, fhp->fh_maxsize-3);

        fhp->fh_handle.fh_size = (datap-fhp->fh_handle.fh_auth+1)*4;


        /* We stuck it there, we know it's good. */
        fhp->fh_dverified = 1;
        nfsd_nr_verified++;
        if (fhp->fh_handle.fh_fileid_type == 255)
                return nfserr_opnotsupp;
        return 0;
}

/*
 * Update file handle information after changing a dentry.
 * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create
 */
int
fh_update(struct svc_fh *fhp)
{
        struct dentry *dentry;
        __u32 *datap;
        
        if (!fhp->fh_dverified)
                goto out_bad;

        dentry = fhp->fh_dentry;
        if (!dentry->d_inode)
                goto out_negative;
        if (fhp->fh_handle.fh_fileid_type != 0)
                goto out_uptodate;
        datap = fhp->fh_handle.fh_auth+
                          fhp->fh_handle.fh_size/4 -1;
        fhp->fh_handle.fh_fileid_type =
                _fh_update(dentry, fhp->fh_export, &datap, fhp->fh_maxsize-fhp->fh_handle.fh_size);
        fhp->fh_handle.fh_size = (datap-fhp->fh_handle.fh_auth+1)*4;
out:
        return 0;

out_bad:
        printk(KERN_ERR "fh_update: fh not verified!\n");
        goto out;
out_negative:
        printk(KERN_ERR "fh_update: %s/%s still negative!\n",
                dentry->d_parent->d_name.name, dentry->d_name.name);
        goto out;
out_uptodate:
        printk(KERN_ERR "fh_update: %s/%s already up-to-date!\n",
                dentry->d_parent->d_name.name, dentry->d_name.name);
        goto out;
}

/*
 * Release a file handle.
 */
void
fh_put(struct svc_fh *fhp)
{
        struct dentry * dentry = fhp->fh_dentry;
        if (fhp->fh_dverified) {
                fh_unlock(fhp);
                fhp->fh_dentry = NULL;
                fhp->fh_dverified = 0;
                dput(dentry);
                nfsd_nr_put++;
        }
        return;
}