Merge ../ntfs-2.6-devel

[mirror_ubuntu-artful-kernel.git] / fs / 9p / vfs_inode.c

/*
 *  linux/fs/9p/vfs_inode.c
 *
 * This file contains vfs inode ops for the 9P2000 protocol.
 *
 *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
 *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to:
 *  Free Software Foundation
 *  51 Franklin Street, Fifth Floor
 *  Boston, MA  02111-1301  USA
 *
 */

#include <linux/module.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/pagemap.h>
#include <linux/stat.h>
#include <linux/string.h>
#include <linux/smp_lock.h>
#include <linux/inet.h>
#include <linux/namei.h>
#include <linux/idr.h>

#include "debug.h"
#include "v9fs.h"
#include "9p.h"
#include "v9fs_vfs.h"
#include "fid.h"

static struct inode_operations v9fs_dir_inode_operations;
static struct inode_operations v9fs_dir_inode_operations_ext;
static struct inode_operations v9fs_file_inode_operations;
static struct inode_operations v9fs_symlink_inode_operations;

/**
 * unixmode2p9mode - convert unix mode bits to plan 9
 * @v9ses: v9fs session information
 * @mode: mode to convert
 *
 */

static int unixmode2p9mode(struct v9fs_session_info *v9ses, int mode)
{
        int res;
        res = mode & 0777;
        if (S_ISDIR(mode))
                res |= V9FS_DMDIR;
        if (v9ses->extended) {
                if (S_ISLNK(mode))
                        res |= V9FS_DMSYMLINK;
                if (v9ses->nodev == 0) {
                        if (S_ISSOCK(mode))
                                res |= V9FS_DMSOCKET;
                        if (S_ISFIFO(mode))
                                res |= V9FS_DMNAMEDPIPE;
                        if (S_ISBLK(mode))
                                res |= V9FS_DMDEVICE;
                        if (S_ISCHR(mode))
                                res |= V9FS_DMDEVICE;
                }

                if ((mode & S_ISUID) == S_ISUID)
                        res |= V9FS_DMSETUID;
                if ((mode & S_ISGID) == S_ISGID)
                        res |= V9FS_DMSETGID;
                if ((mode & V9FS_DMLINK))
                        res |= V9FS_DMLINK;
        }

        return res;
}

/**
 * p9mode2unixmode- convert plan9 mode bits to unix mode bits
 * @v9ses: v9fs session information
 * @mode: mode to convert
 *
 */

static int p9mode2unixmode(struct v9fs_session_info *v9ses, int mode)
{
        int res;

        res = mode & 0777;

        if ((mode & V9FS_DMDIR) == V9FS_DMDIR)
                res |= S_IFDIR;
        else if ((mode & V9FS_DMSYMLINK) && (v9ses->extended))
                res |= S_IFLNK;
        else if ((mode & V9FS_DMSOCKET) && (v9ses->extended)
                 && (v9ses->nodev == 0))
                res |= S_IFSOCK;
        else if ((mode & V9FS_DMNAMEDPIPE) && (v9ses->extended)
                 && (v9ses->nodev == 0))
                res |= S_IFIFO;
        else if ((mode & V9FS_DMDEVICE) && (v9ses->extended)
                 && (v9ses->nodev == 0))
                res |= S_IFBLK;
        else
                res |= S_IFREG;

        if (v9ses->extended) {
                if ((mode & V9FS_DMSETUID) == V9FS_DMSETUID)
                        res |= S_ISUID;

                if ((mode & V9FS_DMSETGID) == V9FS_DMSETGID)
                        res |= S_ISGID;
        }

        return res;
}

/**
 * v9fs_blank_wstat - helper function to setup a 9P stat structure
 * @v9ses: 9P session info (for determining extended mode)
 * @wstat: structure to initialize
 *
 */

static void
v9fs_blank_wstat(struct v9fs_wstat *wstat)
{
        wstat->type = ~0;
        wstat->dev = ~0;
        wstat->qid.type = ~0;
        wstat->qid.version = ~0;
        *((long long *)&wstat->qid.path) = ~0;
        wstat->mode = ~0;
        wstat->atime = ~0;
        wstat->mtime = ~0;
        wstat->length = ~0;
        wstat->name = NULL;
        wstat->uid = NULL;
        wstat->gid = NULL;
        wstat->muid = NULL;
        wstat->n_uid = ~0;
        wstat->n_gid = ~0;
        wstat->n_muid = ~0;
        wstat->extension = NULL;
}

/**
 * v9fs_get_inode - helper function to setup an inode
 * @sb: superblock
 * @mode: mode to setup inode with
 *
 */

struct inode *v9fs_get_inode(struct super_block *sb, int mode)
{
        struct inode *inode = NULL;
        struct v9fs_session_info *v9ses = sb->s_fs_info;

        dprintk(DEBUG_VFS, "super block: %p mode: %o\n", sb, mode);

        inode = new_inode(sb);
        if (inode) {
                inode->i_mode = mode;
                inode->i_uid = current->fsuid;
                inode->i_gid = current->fsgid;
                inode->i_blksize = sb->s_blocksize;
                inode->i_blocks = 0;
                inode->i_rdev = 0;
                inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
                inode->i_mapping->a_ops = &v9fs_addr_operations;

                switch (mode & S_IFMT) {
                case S_IFIFO:
                case S_IFBLK:
                case S_IFCHR:
                case S_IFSOCK:
                        if(!v9ses->extended) {
                                dprintk(DEBUG_ERROR, "special files without extended mode\n");
                                return ERR_PTR(-EINVAL);
                        }
                        init_special_inode(inode, inode->i_mode,
                                           inode->i_rdev);
                        break;
                case S_IFREG:
                        inode->i_op = &v9fs_file_inode_operations;
                        inode->i_fop = &v9fs_file_operations;
                        break;
                case S_IFLNK:
                        if(!v9ses->extended) {
                                dprintk(DEBUG_ERROR, "extended modes used w/o 9P2000.u\n");
                                return ERR_PTR(-EINVAL);
                        }
                        inode->i_op = &v9fs_symlink_inode_operations;
                        break;
                case S_IFDIR:
                        inode->i_nlink++;
                        if(v9ses->extended)
                                inode->i_op = &v9fs_dir_inode_operations_ext;
                        else
                                inode->i_op = &v9fs_dir_inode_operations;
                        inode->i_fop = &v9fs_dir_operations;
                        break;
                default:
                        dprintk(DEBUG_ERROR, "BAD mode 0x%x S_IFMT 0x%x\n",
                                mode, mode & S_IFMT);
                        return ERR_PTR(-EINVAL);
                }
        } else {
                eprintk(KERN_WARNING, "Problem allocating inode\n");
                return ERR_PTR(-ENOMEM);
        }
        return inode;
}

/**
 * v9fs_create - helper function to create files and directories
 * @dir: directory inode file is being created in
 * @file_dentry: dentry file is being created in
 * @perm: permissions file is being created with
 * @open_mode: resulting open mode for file
 *
 */

static int
v9fs_create(struct inode *dir,
            struct dentry *file_dentry,
            unsigned int perm, unsigned int open_mode)
{
        struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dir);
        struct super_block *sb = dir->i_sb;
        struct v9fs_fid *dirfid =
            v9fs_fid_lookup(file_dentry->d_parent);
        struct v9fs_fid *fid = NULL;
        struct inode *file_inode = NULL;
        struct v9fs_fcall *fcall = NULL;
        struct v9fs_qid qid;
        int dirfidnum = -1;
        long newfid = -1;
        int result = 0;
        unsigned int iounit = 0;
        int wfidno = -1;
        int err;

        perm = unixmode2p9mode(v9ses, perm);

        dprintk(DEBUG_VFS, "dir: %p dentry: %p perm: %o mode: %o\n", dir,
                file_dentry, perm, open_mode);

        if (!dirfid)
                return -EBADF;

        dirfidnum = dirfid->fid;
        if (dirfidnum < 0) {
                dprintk(DEBUG_ERROR, "No fid for the directory #%lu\n",
                        dir->i_ino);
                return -EBADF;
        }

        if (file_dentry->d_inode) {
                dprintk(DEBUG_ERROR,
                        "Odd. There is an inode for dir %lu, name :%s:\n",
                        dir->i_ino, file_dentry->d_name.name);
                return -EEXIST;
        }

        newfid = v9fs_get_idpool(&v9ses->fidpool);
        if (newfid < 0) {
                eprintk(KERN_WARNING, "no free fids available\n");
                return -ENOSPC;
        }

        result = v9fs_t_walk(v9ses, dirfidnum, newfid, NULL, &fcall);
        if (result < 0) {
                PRINT_FCALL_ERROR("clone error", fcall);
                v9fs_put_idpool(newfid, &v9ses->fidpool);
                newfid = -1;
                goto CleanUpFid;
        }

        kfree(fcall);
        fcall = NULL;

        result = v9fs_t_create(v9ses, newfid, (char *)file_dentry->d_name.name,
                               perm, open_mode, &fcall);
        if (result < 0) {
                PRINT_FCALL_ERROR("create fails", fcall);
                goto CleanUpFid;
        }

        iounit = fcall->params.rcreate.iounit;
        qid = fcall->params.rcreate.qid;
        kfree(fcall);
        fcall = NULL;

        if (!(perm&V9FS_DMDIR)) {
                fid = v9fs_fid_create(file_dentry, v9ses, newfid, 1);
                dprintk(DEBUG_VFS, "fid %p %d\n", fid, fid->fidcreate);
                if (!fid) {
                        result = -ENOMEM;
                        goto CleanUpFid;
                }

                fid->qid = qid;
                fid->iounit = iounit;
        } else {
                err = v9fs_t_clunk(v9ses, newfid);
                newfid = -1;
                if (err < 0)
                        dprintk(DEBUG_ERROR, "clunk for mkdir failed: %d\n", err);
        }

        /* walk to the newly created file and put the fid in the dentry */
        wfidno = v9fs_get_idpool(&v9ses->fidpool);
        if (wfidno < 0) {
                eprintk(KERN_WARNING, "no free fids available\n");
                return -ENOSPC;
        }

        result = v9fs_t_walk(v9ses, dirfidnum, wfidno,
                (char *) file_dentry->d_name.name, &fcall);
        if (result < 0) {
                PRINT_FCALL_ERROR("clone error", fcall);
                v9fs_put_idpool(wfidno, &v9ses->fidpool);
                wfidno = -1;
                goto CleanUpFid;
        }
        kfree(fcall);
        fcall = NULL;

        if (!v9fs_fid_create(file_dentry, v9ses, wfidno, 0)) {
                v9fs_put_idpool(wfidno, &v9ses->fidpool);

                goto CleanUpFid;
        }

        if ((perm & V9FS_DMSYMLINK) || (perm & V9FS_DMLINK) ||
            (perm & V9FS_DMNAMEDPIPE) || (perm & V9FS_DMSOCKET) ||
            (perm & V9FS_DMDEVICE))
                return 0;

        result = v9fs_t_stat(v9ses, wfidno, &fcall);
        if (result < 0) {
                PRINT_FCALL_ERROR("stat error", fcall);
                goto CleanUpFid;
        }


        file_inode = v9fs_get_inode(sb,
                p9mode2unixmode(v9ses, fcall->params.rstat.stat.mode));

        if ((!file_inode) || IS_ERR(file_inode)) {
                dprintk(DEBUG_ERROR, "create inode failed\n");
                result = -EBADF;
                goto CleanUpFid;
        }

        v9fs_stat2inode(&fcall->params.rstat.stat, file_inode, sb);
        kfree(fcall);
        fcall = NULL;
        file_dentry->d_op = &v9fs_dentry_operations;
        d_instantiate(file_dentry, file_inode);

        return 0;

      CleanUpFid:
        kfree(fcall);
        fcall = NULL;

        if (newfid >= 0) {
                err = v9fs_t_clunk(v9ses, newfid);
                if (err < 0)
                        dprintk(DEBUG_ERROR, "clunk failed: %d\n", err);
        }
        if (wfidno >= 0) {
                err = v9fs_t_clunk(v9ses, wfidno);
                if (err < 0)
                        dprintk(DEBUG_ERROR, "clunk failed: %d\n", err);
        }
        return result;
}

/**
 * v9fs_remove - helper function to remove files and directories
 * @dir: directory inode that is being deleted
 * @file:  dentry that is being deleted
 * @rmdir: removing a directory
 *
 */

static int v9fs_remove(struct inode *dir, struct dentry *file, int rmdir)
{
        struct v9fs_fcall *fcall = NULL;
        struct super_block *sb = NULL;
        struct v9fs_session_info *v9ses = NULL;
        struct v9fs_fid *v9fid = NULL;
        struct inode *file_inode = NULL;
        int fid = -1;
        int result = 0;

        dprintk(DEBUG_VFS, "inode: %p dentry: %p rmdir: %d\n", dir, file,
                rmdir);

        file_inode = file->d_inode;
        sb = file_inode->i_sb;
        v9ses = v9fs_inode2v9ses(file_inode);
        v9fid = v9fs_fid_lookup(file);

        if (!v9fid) {
                dprintk(DEBUG_ERROR,
                        "no v9fs_fid\n");
                return -EBADF;
        }

        fid = v9fid->fid;
        if (fid < 0) {
                dprintk(DEBUG_ERROR, "inode #%lu, no fid!\n",
                        file_inode->i_ino);
                return -EBADF;
        }

        result = v9fs_t_remove(v9ses, fid, &fcall);
        if (result < 0) {
                PRINT_FCALL_ERROR("remove fails", fcall);
        } else {
                v9fs_put_idpool(fid, &v9ses->fidpool);
                v9fs_fid_destroy(v9fid);
        }

        kfree(fcall);
        return result;
}

/**
 * v9fs_vfs_create - VFS hook to create files
 * @inode: directory inode that is being deleted
 * @dentry:  dentry that is being deleted
 * @perm: create permissions
 * @nd: path information
 *
 */

static int
v9fs_vfs_create(struct inode *inode, struct dentry *dentry, int perm,
                struct nameidata *nd)
{
        return v9fs_create(inode, dentry, perm, O_RDWR);
}

/**
 * v9fs_vfs_mkdir - VFS mkdir hook to create a directory
 * @inode:  inode that is being unlinked
 * @dentry: dentry that is being unlinked
 * @mode: mode for new directory
 *
 */

static int v9fs_vfs_mkdir(struct inode *inode, struct dentry *dentry, int mode)
{
        return v9fs_create(inode, dentry, mode | S_IFDIR, O_RDONLY);
}

/**
 * v9fs_vfs_lookup - VFS lookup hook to "walk" to a new inode
 * @dir:  inode that is being walked from
 * @dentry: dentry that is being walked to?
 * @nameidata: path data
 *
 */

static struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
                                      struct nameidata *nameidata)
{
        struct super_block *sb;
        struct v9fs_session_info *v9ses;
        struct v9fs_fid *dirfid;
        struct v9fs_fid *fid;
        struct inode *inode;
        struct v9fs_fcall *fcall = NULL;
        int dirfidnum = -1;
        int newfid = -1;
        int result = 0;

        dprintk(DEBUG_VFS, "dir: %p dentry: (%s) %p nameidata: %p\n",
                dir, dentry->d_iname, dentry, nameidata);

        sb = dir->i_sb;
        v9ses = v9fs_inode2v9ses(dir);
        dirfid = v9fs_fid_lookup(dentry->d_parent);

        if (!dirfid) {
                dprintk(DEBUG_ERROR, "no dirfid\n");
                return ERR_PTR(-EINVAL);
        }

        dirfidnum = dirfid->fid;

        if (dirfidnum < 0) {
                dprintk(DEBUG_ERROR, "no dirfid for inode %p, #%lu\n",
                        dir, dir->i_ino);
                return ERR_PTR(-EBADF);
        }

        newfid = v9fs_get_idpool(&v9ses->fidpool);
        if (newfid < 0) {
                eprintk(KERN_WARNING, "newfid fails!\n");
                return ERR_PTR(-ENOSPC);
        }

        result =
            v9fs_t_walk(v9ses, dirfidnum, newfid, (char *)dentry->d_name.name,
                        NULL);
        if (result < 0) {
                v9fs_put_idpool(newfid, &v9ses->fidpool);
                if (result == -ENOENT) {
                        d_add(dentry, NULL);
                        dprintk(DEBUG_VFS,
                                "Return negative dentry %p count %d\n",
                                dentry, atomic_read(&dentry->d_count));
                        return NULL;
                }
                dprintk(DEBUG_ERROR, "walk error:%d\n", result);
                goto FreeFcall;
        }

        result = v9fs_t_stat(v9ses, newfid, &fcall);
        if (result < 0) {
                dprintk(DEBUG_ERROR, "stat error\n");
                goto FreeFcall;
        }

        inode = v9fs_get_inode(sb, p9mode2unixmode(v9ses,
                fcall->params.rstat.stat.mode));

        if (IS_ERR(inode) && (PTR_ERR(inode) == -ENOSPC)) {
                eprintk(KERN_WARNING, "inode alloc failes, returns %ld\n",
                        PTR_ERR(inode));

                result = -ENOSPC;
                goto FreeFcall;
        }

        inode->i_ino = v9fs_qid2ino(&fcall->params.rstat.stat.qid);

        fid = v9fs_fid_create(dentry, v9ses, newfid, 0);
        if (fid == NULL) {
                dprintk(DEBUG_ERROR, "couldn't insert\n");
                result = -ENOMEM;
                goto FreeFcall;
        }

        fid->qid = fcall->params.rstat.stat.qid;

        dentry->d_op = &v9fs_dentry_operations;
        v9fs_stat2inode(&fcall->params.rstat.stat, inode, inode->i_sb);

        d_add(dentry, inode);
        kfree(fcall);

        return NULL;

      FreeFcall:
        kfree(fcall);
        return ERR_PTR(result);
}

/**
 * v9fs_vfs_unlink - VFS unlink hook to delete an inode
 * @i:  inode that is being unlinked
 * @d: dentry that is being unlinked
 *
 */

static int v9fs_vfs_unlink(struct inode *i, struct dentry *d)
{
        return v9fs_remove(i, d, 0);
}

/**
 * v9fs_vfs_rmdir - VFS unlink hook to delete a directory
 * @i:  inode that is being unlinked
 * @d: dentry that is being unlinked
 *
 */

static int v9fs_vfs_rmdir(struct inode *i, struct dentry *d)
{
        return v9fs_remove(i, d, 1);
}

/**
 * v9fs_vfs_rename - VFS hook to rename an inode
 * @old_dir:  old dir inode
 * @old_dentry: old dentry
 * @new_dir: new dir inode
 * @new_dentry: new dentry
 *
 */

static int
v9fs_vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
                struct inode *new_dir, struct dentry *new_dentry)
{
        struct inode *old_inode = old_dentry->d_inode;
        struct v9fs_session_info *v9ses = v9fs_inode2v9ses(old_inode);
        struct v9fs_fid *oldfid = v9fs_fid_lookup(old_dentry);
        struct v9fs_fid *olddirfid =
            v9fs_fid_lookup(old_dentry->d_parent);
        struct v9fs_fid *newdirfid =
            v9fs_fid_lookup(new_dentry->d_parent);
        struct v9fs_wstat wstat;
        struct v9fs_fcall *fcall = NULL;
        int fid = -1;
        int olddirfidnum = -1;
        int newdirfidnum = -1;
        int retval = 0;

        dprintk(DEBUG_VFS, "\n");

        if ((!oldfid) || (!olddirfid) || (!newdirfid)) {
                dprintk(DEBUG_ERROR, "problem with arguments\n");
                return -EBADF;
        }

        /* 9P can only handle file rename in the same directory */
        if (memcmp(&olddirfid->qid, &newdirfid->qid, sizeof(newdirfid->qid))) {
                dprintk(DEBUG_ERROR, "old dir and new dir are different\n");
                retval = -EPERM;
                goto FreeFcallnBail;
        }

        fid = oldfid->fid;
        olddirfidnum = olddirfid->fid;
        newdirfidnum = newdirfid->fid;

        if (fid < 0) {
                dprintk(DEBUG_ERROR, "no fid for old file #%lu\n",
                        old_inode->i_ino);
                retval = -EBADF;
                goto FreeFcallnBail;
        }

        v9fs_blank_wstat(&wstat);
        wstat.muid = v9ses->name;
        wstat.name = (char *) new_dentry->d_name.name;

        retval = v9fs_t_wstat(v9ses, fid, &wstat, &fcall);

      FreeFcallnBail:
        if (retval < 0)
                PRINT_FCALL_ERROR("wstat error", fcall);

        kfree(fcall);
        return retval;
}

/**
 * v9fs_vfs_getattr - retrieve file metadata
 * @mnt - mount information
 * @dentry - file to get attributes on
 * @stat - metadata structure to populate
 *
 */

static int
v9fs_vfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
                 struct kstat *stat)
{
        struct v9fs_fcall *fcall = NULL;
        struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dentry->d_inode);
        struct v9fs_fid *fid = v9fs_fid_lookup(dentry);
        int err = -EPERM;

        dprintk(DEBUG_VFS, "dentry: %p\n", dentry);
        if (!fid) {
                dprintk(DEBUG_ERROR,
                        "couldn't find fid associated with dentry\n");
                return -EBADF;
        }

        err = v9fs_t_stat(v9ses, fid->fid, &fcall);

        if (err < 0)
                dprintk(DEBUG_ERROR, "stat error\n");
        else {
                v9fs_stat2inode(&fcall->params.rstat.stat, dentry->d_inode,
                                  dentry->d_inode->i_sb);
                generic_fillattr(dentry->d_inode, stat);
        }

        kfree(fcall);
        return err;
}

/**
 * v9fs_vfs_setattr - set file metadata
 * @dentry: file whose metadata to set
 * @iattr: metadata assignment structure
 *
 */

static int v9fs_vfs_setattr(struct dentry *dentry, struct iattr *iattr)
{
        struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dentry->d_inode);
        struct v9fs_fid *fid = v9fs_fid_lookup(dentry);
        struct v9fs_fcall *fcall = NULL;
        struct v9fs_wstat wstat;
        int res = -EPERM;

        dprintk(DEBUG_VFS, "\n");

        if (!fid) {
                dprintk(DEBUG_ERROR,
                        "Couldn't find fid associated with dentry\n");
                return -EBADF;
        }

        v9fs_blank_wstat(&wstat);
        if (iattr->ia_valid & ATTR_MODE)
                wstat.mode = unixmode2p9mode(v9ses, iattr->ia_mode);

        if (iattr->ia_valid & ATTR_MTIME)
                wstat.mtime = iattr->ia_mtime.tv_sec;

        if (iattr->ia_valid & ATTR_ATIME)
                wstat.atime = iattr->ia_atime.tv_sec;

        if (iattr->ia_valid & ATTR_SIZE)
                wstat.length = iattr->ia_size;

        if (v9ses->extended) {
                if (iattr->ia_valid & ATTR_UID)
                        wstat.n_uid = iattr->ia_uid;

                if (iattr->ia_valid & ATTR_GID)
                        wstat.n_gid = iattr->ia_gid;
        }

        res = v9fs_t_wstat(v9ses, fid->fid, &wstat, &fcall);

        if (res < 0)
                PRINT_FCALL_ERROR("wstat error", fcall);

        kfree(fcall);
        if (res >= 0)
                res = inode_setattr(dentry->d_inode, iattr);

        return res;
}

/**
 * v9fs_stat2inode - populate an inode structure with mistat info
 * @stat: Plan 9 metadata (mistat) structure
 * @inode: inode to populate
 * @sb: superblock of filesystem
 *
 */

void
v9fs_stat2inode(struct v9fs_stat *stat, struct inode *inode,
        struct super_block *sb)
{
        int n;
        char ext[32];
        struct v9fs_session_info *v9ses = sb->s_fs_info;

        inode->i_nlink = 1;

        inode->i_atime.tv_sec = stat->atime;
        inode->i_mtime.tv_sec = stat->mtime;
        inode->i_ctime.tv_sec = stat->mtime;

        inode->i_uid = v9ses->uid;
        inode->i_gid = v9ses->gid;

        if (v9ses->extended) {
                inode->i_uid = stat->n_uid;
                inode->i_gid = stat->n_gid;
        }

        inode->i_mode = p9mode2unixmode(v9ses, stat->mode);
        if ((S_ISBLK(inode->i_mode)) || (S_ISCHR(inode->i_mode))) {
                char type = 0;
                int major = -1;
                int minor = -1;

                n = stat->extension.len;
                if (n > sizeof(ext)-1)
                        n = sizeof(ext)-1;
                memmove(ext, stat->extension.str, n);
                ext[n] = 0;
                sscanf(ext, "%c %u %u", &type, &major, &minor);
                switch (type) {
                case 'c':
                        inode->i_mode &= ~S_IFBLK;
                        inode->i_mode |= S_IFCHR;
                        break;
                case 'b':
                        break;
                default:
                        dprintk(DEBUG_ERROR, "Unknown special type %c (%.*s)\n",
                                type, stat->extension.len, stat->extension.str);
                };
                inode->i_rdev = MKDEV(major, minor);
        } else
                inode->i_rdev = 0;

        inode->i_size = stat->length;

        inode->i_blksize = sb->s_blocksize;
        inode->i_blocks =
            (inode->i_size + inode->i_blksize - 1) >> sb->s_blocksize_bits;
}

/**
 * v9fs_qid2ino - convert qid into inode number
 * @qid: qid to hash
 *
 * BUG: potential for inode number collisions?
 */

ino_t v9fs_qid2ino(struct v9fs_qid *qid)
{
        u64 path = qid->path + 2;
        ino_t i = 0;

        if (sizeof(ino_t) == sizeof(path))
                memcpy(&i, &path, sizeof(ino_t));
        else
                i = (ino_t) (path ^ (path >> 32));

        return i;
}

/**
 * v9fs_readlink - read a symlink's location (internal version)
 * @dentry: dentry for symlink
 * @buffer: buffer to load symlink location into
 * @buflen: length of buffer
 *
 */

static int v9fs_readlink(struct dentry *dentry, char *buffer, int buflen)
{
        int retval = -EPERM;

        struct v9fs_fcall *fcall = NULL;
        struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dentry->d_inode);
        struct v9fs_fid *fid = v9fs_fid_lookup(dentry);

        if (!fid) {
                dprintk(DEBUG_ERROR, "could not resolve fid from dentry\n");
                retval = -EBADF;
                goto FreeFcall;
        }

        if (!v9ses->extended) {
                retval = -EBADF;
                dprintk(DEBUG_ERROR, "not extended\n");
                goto FreeFcall;
        }

        dprintk(DEBUG_VFS, " %s\n", dentry->d_name.name);
        retval = v9fs_t_stat(v9ses, fid->fid, &fcall);

        if (retval < 0) {
                dprintk(DEBUG_ERROR, "stat error\n");
                goto FreeFcall;
        }

        if (!fcall)
                return -EIO;

        if (!(fcall->params.rstat.stat.mode & V9FS_DMSYMLINK)) {
                retval = -EINVAL;
                goto FreeFcall;
        }

        /* copy extension buffer into buffer */
        if (fcall->params.rstat.stat.extension.len+1 < buflen)
                buflen = fcall->params.rstat.stat.extension.len + 1;

        memcpy(buffer, fcall->params.rstat.stat.extension.str, buflen - 1);
        buffer[buflen-1] = 0;

        retval = buflen;

      FreeFcall:
        kfree(fcall);

        return retval;
}

/**
 * v9fs_vfs_readlink - read a symlink's location
 * @dentry: dentry for symlink
 * @buf: buffer to load symlink location into
 * @buflen: length of buffer
 *
 */

static int v9fs_vfs_readlink(struct dentry *dentry, char __user * buffer,
                             int buflen)
{
        int retval;
        int ret;
        char *link = __getname();

        if (buflen > PATH_MAX)
                buflen = PATH_MAX;

        dprintk(DEBUG_VFS, " dentry: %s (%p)\n", dentry->d_iname, dentry);

        retval = v9fs_readlink(dentry, link, buflen);

        if (retval > 0) {
                if ((ret = copy_to_user(buffer, link, retval)) != 0) {
                        dprintk(DEBUG_ERROR, "problem copying to user: %d\n",
                                ret);
                        retval = ret;
                }
        }

        __putname(link);
        return retval;
}

/**
 * v9fs_vfs_follow_link - follow a symlink path
 * @dentry: dentry for symlink
 * @nd: nameidata
 *
 */

static void *v9fs_vfs_follow_link(struct dentry *dentry, struct nameidata *nd)
{
        int len = 0;
        char *link = __getname();

        dprintk(DEBUG_VFS, "%s n", dentry->d_name.name);

        if (!link)
                link = ERR_PTR(-ENOMEM);
        else {
                len = v9fs_readlink(dentry, link, PATH_MAX);

                if (len < 0) {
                        __putname(link);
                        link = ERR_PTR(len);
                } else
                        link[len] = 0;
        }
        nd_set_link(nd, link);

        return NULL;
}

/**
 * v9fs_vfs_put_link - release a symlink path
 * @dentry: dentry for symlink
 * @nd: nameidata
 *
 */

static void v9fs_vfs_put_link(struct dentry *dentry, struct nameidata *nd, void *p)
{
        char *s = nd_get_link(nd);

        dprintk(DEBUG_VFS, " %s %s\n", dentry->d_name.name, s);
        if (!IS_ERR(s))
                __putname(s);
}

static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
        int mode, const char *extension)
{
        int err, retval;
        struct v9fs_session_info *v9ses;
        struct v9fs_fcall *fcall;
        struct v9fs_fid *fid;
        struct v9fs_wstat wstat;

        v9ses = v9fs_inode2v9ses(dir);
        retval = -EPERM;
        fcall = NULL;

        if (!v9ses->extended) {
                dprintk(DEBUG_ERROR, "not extended\n");
                goto free_mem;
        }

        /* issue a create */
        retval = v9fs_create(dir, dentry, mode, 0);
        if (retval != 0)
                goto free_mem;

        fid = v9fs_fid_get_created(dentry);
        if (!fid) {
                dprintk(DEBUG_ERROR, "couldn't resolve fid from dentry\n");
                goto free_mem;
        }

        /* issue a Twstat */
        v9fs_blank_wstat(&wstat);
        wstat.muid = v9ses->name;
        wstat.extension = (char *) extension;
        retval = v9fs_t_wstat(v9ses, fid->fid, &wstat, &fcall);
        if (retval < 0) {
                PRINT_FCALL_ERROR("wstat error", fcall);
                goto free_mem;
        }

        err = v9fs_t_clunk(v9ses, fid->fid);
        if (err < 0) {
                dprintk(DEBUG_ERROR, "clunk failed: %d\n", err);
                goto free_mem;
        }

        d_drop(dentry);         /* FID - will this also clunk? */

free_mem:
        kfree(fcall);
        return retval;
}

/**
 * v9fs_vfs_symlink - helper function to create symlinks
 * @dir: directory inode containing symlink
 * @dentry: dentry for symlink
 * @symname: symlink data
 *
 * See 9P2000.u RFC for more information
 *
 */

static int
v9fs_vfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
{
        dprintk(DEBUG_VFS, " %lu,%s,%s\n", dir->i_ino, dentry->d_name.name,
                symname);

        return v9fs_vfs_mkspecial(dir, dentry, S_IFLNK, symname);
}

/**
 * v9fs_vfs_link - create a hardlink
 * @old_dentry: dentry for file to link to
 * @dir: inode destination for new link
 * @dentry: dentry for link
 *
 */

/* XXX - lots of code dup'd from symlink and creates,
 * figure out a better reuse strategy
 */

static int
v9fs_vfs_link(struct dentry *old_dentry, struct inode *dir,
              struct dentry *dentry)
{
        int retval;
        struct v9fs_fid *oldfid;
        char *name;

        dprintk(DEBUG_VFS, " %lu,%s,%s\n", dir->i_ino, dentry->d_name.name,
                old_dentry->d_name.name);

        oldfid = v9fs_fid_lookup(old_dentry);
        if (!oldfid) {
                dprintk(DEBUG_ERROR, "can't find oldfid\n");
                return -EPERM;
        }

        name = __getname();
        sprintf(name, "hardlink(%d)\n", oldfid->fid);
        retval = v9fs_vfs_mkspecial(dir, dentry, V9FS_DMLINK, name);
        __putname(name);

        return retval;
}

/**
 * v9fs_vfs_mknod - create a special file
 * @dir: inode destination for new link
 * @dentry: dentry for file
 * @mode: mode for creation
 * @dev_t: device associated with special file
 *
 */

static int
v9fs_vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t rdev)
{
        int retval;
        char *name;

        dprintk(DEBUG_VFS, " %lu,%s mode: %x MAJOR: %u MINOR: %u\n", dir->i_ino,
                dentry->d_name.name, mode, MAJOR(rdev), MINOR(rdev));

        if (!new_valid_dev(rdev))
                return -EINVAL;

        name = __getname();
        /* build extension */
        if (S_ISBLK(mode))
                sprintf(name, "b %u %u", MAJOR(rdev), MINOR(rdev));
        else if (S_ISCHR(mode))
                sprintf(name, "c %u %u", MAJOR(rdev), MINOR(rdev));
        else if (S_ISFIFO(mode))
                *name = 0;
        else {
                __putname(name);
                return -EINVAL;
        }

        retval = v9fs_vfs_mkspecial(dir, dentry, mode, name);
        __putname(name);

        return retval;
}

static struct inode_operations v9fs_dir_inode_operations_ext = {
        .create = v9fs_vfs_create,
        .lookup = v9fs_vfs_lookup,
        .symlink = v9fs_vfs_symlink,
        .link = v9fs_vfs_link,
        .unlink = v9fs_vfs_unlink,
        .mkdir = v9fs_vfs_mkdir,
        .rmdir = v9fs_vfs_rmdir,
        .mknod = v9fs_vfs_mknod,
        .rename = v9fs_vfs_rename,
        .readlink = v9fs_vfs_readlink,
        .getattr = v9fs_vfs_getattr,
        .setattr = v9fs_vfs_setattr,
};

static struct inode_operations v9fs_dir_inode_operations = {
        .create = v9fs_vfs_create,
        .lookup = v9fs_vfs_lookup,
        .unlink = v9fs_vfs_unlink,
        .mkdir = v9fs_vfs_mkdir,
        .rmdir = v9fs_vfs_rmdir,
        .mknod = v9fs_vfs_mknod,
        .rename = v9fs_vfs_rename,
        .getattr = v9fs_vfs_getattr,
        .setattr = v9fs_vfs_setattr,
};

static struct inode_operations v9fs_file_inode_operations = {
        .getattr = v9fs_vfs_getattr,
        .setattr = v9fs_vfs_setattr,
};

static struct inode_operations v9fs_symlink_inode_operations = {
        .readlink = v9fs_vfs_readlink,
        .follow_link = v9fs_vfs_follow_link,
        .put_link = v9fs_vfs_put_link,
        .getattr = v9fs_vfs_getattr,
        .setattr = v9fs_vfs_setattr,
};