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root/net/9p/client.c

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DEFINITIONS

This source file includes following definitions.
  1. parse_opts
  2. p9_client_rpc
  3. p9_client_create
  4. p9_client_destroy
  5. p9_client_disconnect
  6. p9_client_attach
  7. p9_client_auth
  8. p9_client_walk
  9. p9_client_open
  10. p9_client_fcreate
  11. p9_client_clunk
  12. p9_client_remove
  13. p9_client_read
  14. p9_client_write
  15. p9_client_uread
  16. p9_client_uwrite
  17. p9_client_readn
  18. p9_client_stat
  19. p9_client_wstat
  20. p9_client_dirread
  21. p9_clone_stat
  22. p9_fid_create
  23. p9_fid_destroy

/*
 * net/9p/clnt.c
 *
 * 9P Client
 *
 *  Copyright (C) 2008 by Eric Van Hensbergen <ericvh@gmail.com>
 *  Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2
 *  as published by the Free Software Foundation.
 *
 *  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/poll.h>
#include <linux/idr.h>
#include <linux/mutex.h>
#include <linux/sched.h>
#include <linux/uaccess.h>
#include <net/9p/9p.h>
#include <linux/parser.h>
#include <net/9p/transport.h>
#include <net/9p/client.h>

static struct p9_fid *p9_fid_create(struct p9_client *clnt);
static void p9_fid_destroy(struct p9_fid *fid);
static struct p9_stat *p9_clone_stat(struct p9_stat *st, int dotu);

/*
  * Client Option Parsing (code inspired by NFS code)
  *  - a little lazy - parse all client options
  */

enum {
        Opt_msize,
        Opt_trans,
        Opt_legacy,
        Opt_err,
};

static const match_table_t tokens = {
        {Opt_msize, "msize=%u"},
        {Opt_legacy, "noextend"},
        {Opt_trans, "trans=%s"},
        {Opt_err, NULL},
};

/**
 * v9fs_parse_options - parse mount options into session structure
 * @options: options string passed from mount
 * @v9ses: existing v9fs session information
 *
 * Return 0 upon success, -ERRNO upon failure
 */

static int parse_opts(char *opts, struct p9_client *clnt)
{
        char *options;
        char *p;
        substring_t args[MAX_OPT_ARGS];
        int option;
        int ret = 0;

        clnt->dotu = 1;
        clnt->msize = 8192;

        if (!opts)
                return 0;

        options = kstrdup(opts, GFP_KERNEL);
        if (!options) {
                P9_DPRINTK(P9_DEBUG_ERROR,
                                "failed to allocate copy of option string\n");
                return -ENOMEM;
        }

        while ((p = strsep(&options, ",")) != NULL) {
                int token;
                if (!*p)
                        continue;
                token = match_token(p, tokens, args);
                if (token < Opt_trans) {
                        int r = match_int(&args[0], &option);
                        if (r < 0) {
                                P9_DPRINTK(P9_DEBUG_ERROR,
                                        "integer field, but no integer?\n");
                                ret = r;
                                continue;
                        }
                }
                switch (token) {
                case Opt_msize:
                        clnt->msize = option;
                        break;
                case Opt_trans:
                        clnt->trans_mod = v9fs_get_trans_by_name(&args[0]);
                        break;
                case Opt_legacy:
                        clnt->dotu = 0;
                        break;
                default:
                        continue;
                }
        }

        if (!clnt->trans_mod)
                clnt->trans_mod = v9fs_get_default_trans();

        kfree(options);
        return ret;
}


/**
 * p9_client_rpc - sends 9P request and waits until a response is available.
 *      The function can be interrupted.
 * @c: client data
 * @tc: request to be sent
 * @rc: pointer where a pointer to the response is stored
 */
int
p9_client_rpc(struct p9_client *c, struct p9_fcall *tc,
        struct p9_fcall **rc)
{
        return c->trans->rpc(c->trans, tc, rc);
}

struct p9_client *p9_client_create(const char *dev_name, char *options)
{
        int err, n;
        struct p9_client *clnt;
        struct p9_fcall *tc, *rc;
        struct p9_str *version;

        err = 0;
        tc = NULL;
        rc = NULL;
        clnt = kmalloc(sizeof(struct p9_client), GFP_KERNEL);
        if (!clnt)
                return ERR_PTR(-ENOMEM);

        clnt->trans_mod = NULL;
        clnt->trans = NULL;
        spin_lock_init(&clnt->lock);
        INIT_LIST_HEAD(&clnt->fidlist);
        clnt->fidpool = p9_idpool_create();
        if (IS_ERR(clnt->fidpool)) {
                err = PTR_ERR(clnt->fidpool);
                clnt->fidpool = NULL;
                goto error;
        }

        err = parse_opts(options, clnt);
        if (err < 0)
                goto error;

        if (clnt->trans_mod == NULL) {
                err = -EPROTONOSUPPORT;
                P9_DPRINTK(P9_DEBUG_ERROR,
                                "No transport defined or default transport\n");
                goto error;
        }

        P9_DPRINTK(P9_DEBUG_9P, "clnt %p trans %p msize %d dotu %d\n",
                clnt, clnt->trans_mod, clnt->msize, clnt->dotu);


        clnt->trans = clnt->trans_mod->create(dev_name, options, clnt->msize,
                                                                clnt->dotu);
        if (IS_ERR(clnt->trans)) {
                err = PTR_ERR(clnt->trans);
                clnt->trans = NULL;
                goto error;
        }

        if ((clnt->msize+P9_IOHDRSZ) > clnt->trans_mod->maxsize)
                clnt->msize = clnt->trans_mod->maxsize-P9_IOHDRSZ;

        tc = p9_create_tversion(clnt->msize, clnt->dotu?"9P2000.u":"9P2000");
        if (IS_ERR(tc)) {
                err = PTR_ERR(tc);
                tc = NULL;
                goto error;
        }

        err = p9_client_rpc(clnt, tc, &rc);
        if (err)
                goto error;

        version = &rc->params.rversion.version;
        if (version->len == 8 && !memcmp(version->str, "9P2000.u", 8))
                clnt->dotu = 1;
        else if (version->len == 6 && !memcmp(version->str, "9P2000", 6))
                clnt->dotu = 0;
        else {
                err = -EREMOTEIO;
                goto error;
        }

        n = rc->params.rversion.msize;
        if (n < clnt->msize)
                clnt->msize = n;

        kfree(tc);
        kfree(rc);
        return clnt;

error:
        kfree(tc);
        kfree(rc);
        p9_client_destroy(clnt);
        return ERR_PTR(err);
}
EXPORT_SYMBOL(p9_client_create);

void p9_client_destroy(struct p9_client *clnt)
{
        struct p9_fid *fid, *fidptr;

        P9_DPRINTK(P9_DEBUG_9P, "clnt %p\n", clnt);

        if (clnt->trans) {
                clnt->trans->close(clnt->trans);
                kfree(clnt->trans);
                clnt->trans = NULL;
        }

        v9fs_put_trans(clnt->trans_mod);

        list_for_each_entry_safe(fid, fidptr, &clnt->fidlist, flist)
                p9_fid_destroy(fid);

        if (clnt->fidpool)
                p9_idpool_destroy(clnt->fidpool);

        kfree(clnt);
}
EXPORT_SYMBOL(p9_client_destroy);

void p9_client_disconnect(struct p9_client *clnt)
{
        P9_DPRINTK(P9_DEBUG_9P, "clnt %p\n", clnt);
        clnt->trans->status = Disconnected;
}
EXPORT_SYMBOL(p9_client_disconnect);

struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
        char *uname, u32 n_uname, char *aname)
{
        int err;
        struct p9_fcall *tc, *rc;
        struct p9_fid *fid;

        P9_DPRINTK(P9_DEBUG_9P, "clnt %p afid %d uname %s aname %s\n",
                clnt, afid?afid->fid:-1, uname, aname);
        err = 0;
        tc = NULL;
        rc = NULL;

        fid = p9_fid_create(clnt);
        if (IS_ERR(fid)) {
                err = PTR_ERR(fid);
                fid = NULL;
                goto error;
        }

        tc = p9_create_tattach(fid->fid, afid?afid->fid:P9_NOFID, uname, aname,
                n_uname, clnt->dotu);
        if (IS_ERR(tc)) {
                err = PTR_ERR(tc);
                tc = NULL;
                goto error;
        }

        err = p9_client_rpc(clnt, tc, &rc);
        if (err)
                goto error;

        memmove(&fid->qid, &rc->params.rattach.qid, sizeof(struct p9_qid));
        kfree(tc);
        kfree(rc);
        return fid;

error:
        kfree(tc);
        kfree(rc);
        if (fid)
                p9_fid_destroy(fid);
        return ERR_PTR(err);
}
EXPORT_SYMBOL(p9_client_attach);

struct p9_fid *p9_client_auth(struct p9_client *clnt, char *uname,
        u32 n_uname, char *aname)
{
        int err;
        struct p9_fcall *tc, *rc;
        struct p9_fid *fid;

        P9_DPRINTK(P9_DEBUG_9P, "clnt %p uname %s aname %s\n", clnt, uname,
                                                                        aname);
        err = 0;
        tc = NULL;
        rc = NULL;

        fid = p9_fid_create(clnt);
        if (IS_ERR(fid)) {
                err = PTR_ERR(fid);
                fid = NULL;
                goto error;
        }

        tc = p9_create_tauth(fid->fid, uname, aname, n_uname, clnt->dotu);
        if (IS_ERR(tc)) {
                err = PTR_ERR(tc);
                tc = NULL;
                goto error;
        }

        err = p9_client_rpc(clnt, tc, &rc);
        if (err)
                goto error;

        memmove(&fid->qid, &rc->params.rauth.qid, sizeof(struct p9_qid));
        kfree(tc);
        kfree(rc);
        return fid;

error:
        kfree(tc);
        kfree(rc);
        if (fid)
                p9_fid_destroy(fid);
        return ERR_PTR(err);
}
EXPORT_SYMBOL(p9_client_auth);

struct p9_fid *p9_client_walk(struct p9_fid *oldfid, int nwname, char **wnames,
        int clone)
{
        int err;
        struct p9_fcall *tc, *rc;
        struct p9_client *clnt;
        struct p9_fid *fid;

        P9_DPRINTK(P9_DEBUG_9P, "fid %d nwname %d wname[0] %s\n",
                oldfid->fid, nwname, wnames?wnames[0]:NULL);
        err = 0;
        tc = NULL;
        rc = NULL;
        clnt = oldfid->clnt;
        if (clone) {
                fid = p9_fid_create(clnt);
                if (IS_ERR(fid)) {
                        err = PTR_ERR(fid);
                        fid = NULL;
                        goto error;
                }

                fid->uid = oldfid->uid;
        } else
                fid = oldfid;

        tc = p9_create_twalk(oldfid->fid, fid->fid, nwname, wnames);
        if (IS_ERR(tc)) {
                err = PTR_ERR(tc);
                tc = NULL;
                goto error;
        }

        err = p9_client_rpc(clnt, tc, &rc);
        if (err) {
                if (rc && rc->id == P9_RWALK)
                        goto clunk_fid;
                else
                        goto error;
        }

        if (rc->params.rwalk.nwqid != nwname) {
                err = -ENOENT;
                goto clunk_fid;
        }

        if (nwname)
                memmove(&fid->qid,
                        &rc->params.rwalk.wqids[rc->params.rwalk.nwqid - 1],
                        sizeof(struct p9_qid));
        else
                fid->qid = oldfid->qid;

        kfree(tc);
        kfree(rc);
        return fid;

clunk_fid:
        kfree(tc);
        kfree(rc);
        rc = NULL;
        tc = p9_create_tclunk(fid->fid);
        if (IS_ERR(tc)) {
                err = PTR_ERR(tc);
                tc = NULL;
                goto error;
        }

        p9_client_rpc(clnt, tc, &rc);

error:
        kfree(tc);
        kfree(rc);
        if (fid && (fid != oldfid))
                p9_fid_destroy(fid);

        return ERR_PTR(err);
}
EXPORT_SYMBOL(p9_client_walk);

int p9_client_open(struct p9_fid *fid, int mode)
{
        int err;
        struct p9_fcall *tc, *rc;
        struct p9_client *clnt;

        P9_DPRINTK(P9_DEBUG_9P, "fid %d mode %d\n", fid->fid, mode);
        err = 0;
        tc = NULL;
        rc = NULL;
        clnt = fid->clnt;

        if (fid->mode != -1)
                return -EINVAL;

        tc = p9_create_topen(fid->fid, mode);
        if (IS_ERR(tc)) {
                err = PTR_ERR(tc);
                tc = NULL;
                goto done;
        }

        err = p9_client_rpc(clnt, tc, &rc);
        if (err)
                goto done;

        fid->mode = mode;
        fid->iounit = rc->params.ropen.iounit;

done:
        kfree(tc);
        kfree(rc);
        return err;
}
EXPORT_SYMBOL(p9_client_open);

int p9_client_fcreate(struct p9_fid *fid, char *name, u32 perm, int mode,
                     char *extension)
{
        int err;
        struct p9_fcall *tc, *rc;
        struct p9_client *clnt;

        P9_DPRINTK(P9_DEBUG_9P, "fid %d name %s perm %d mode %d\n", fid->fid,
                name, perm, mode);
        err = 0;
        tc = NULL;
        rc = NULL;
        clnt = fid->clnt;

        if (fid->mode != -1)
                return -EINVAL;

        tc = p9_create_tcreate(fid->fid, name, perm, mode, extension,
                                                               clnt->dotu);
        if (IS_ERR(tc)) {
                err = PTR_ERR(tc);
                tc = NULL;
                goto done;
        }

        err = p9_client_rpc(clnt, tc, &rc);
        if (err)
                goto done;

        fid->mode = mode;
        fid->iounit = rc->params.ropen.iounit;

done:
        kfree(tc);
        kfree(rc);
        return err;
}
EXPORT_SYMBOL(p9_client_fcreate);

int p9_client_clunk(struct p9_fid *fid)
{
        int err;
        struct p9_fcall *tc, *rc;
        struct p9_client *clnt;

        P9_DPRINTK(P9_DEBUG_9P, "fid %d\n", fid->fid);
        err = 0;
        tc = NULL;
        rc = NULL;
        clnt = fid->clnt;

        tc = p9_create_tclunk(fid->fid);
        if (IS_ERR(tc)) {
                err = PTR_ERR(tc);
                tc = NULL;
                goto done;
        }

        err = p9_client_rpc(clnt, tc, &rc);
        if (err)
                goto done;

        p9_fid_destroy(fid);

done:
        kfree(tc);
        kfree(rc);
        return err;
}
EXPORT_SYMBOL(p9_client_clunk);

int p9_client_remove(struct p9_fid *fid)
{
        int err;
        struct p9_fcall *tc, *rc;
        struct p9_client *clnt;

        P9_DPRINTK(P9_DEBUG_9P, "fid %d\n", fid->fid);
        err = 0;
        tc = NULL;
        rc = NULL;
        clnt = fid->clnt;

        tc = p9_create_tremove(fid->fid);
        if (IS_ERR(tc)) {
                err = PTR_ERR(tc);
                tc = NULL;
                goto done;
        }

        err = p9_client_rpc(clnt, tc, &rc);
        if (err)
                goto done;

        p9_fid_destroy(fid);

done:
        kfree(tc);
        kfree(rc);
        return err;
}
EXPORT_SYMBOL(p9_client_remove);

int p9_client_read(struct p9_fid *fid, char *data, u64 offset, u32 count)
{
        int err, n, rsize, total;
        struct p9_fcall *tc, *rc;
        struct p9_client *clnt;

        P9_DPRINTK(P9_DEBUG_9P, "fid %d offset %llu %d\n", fid->fid,
                                        (long long unsigned) offset, count);
        err = 0;
        tc = NULL;
        rc = NULL;
        clnt = fid->clnt;
        total = 0;

        rsize = fid->iounit;
        if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
                rsize = clnt->msize - P9_IOHDRSZ;

        do {
                if (count < rsize)
                        rsize = count;

                tc = p9_create_tread(fid->fid, offset, rsize);
                if (IS_ERR(tc)) {
                        err = PTR_ERR(tc);
                        tc = NULL;
                        goto error;
                }

                err = p9_client_rpc(clnt, tc, &rc);
                if (err)
                        goto error;

                n = rc->params.rread.count;
                if (n > count)
                        n = count;

                memmove(data, rc->params.rread.data, n);
                count -= n;
                data += n;
                offset += n;
                total += n;
                kfree(tc);
                tc = NULL;
                kfree(rc);
                rc = NULL;
        } while (count > 0 && n == rsize);

        return total;

error:
        kfree(tc);
        kfree(rc);
        return err;
}
EXPORT_SYMBOL(p9_client_read);

int p9_client_write(struct p9_fid *fid, char *data, u64 offset, u32 count)
{
        int err, n, rsize, total;
        struct p9_fcall *tc, *rc;
        struct p9_client *clnt;

        P9_DPRINTK(P9_DEBUG_9P, "fid %d offset %llu count %d\n", fid->fid,
                                        (long long unsigned) offset, count);
        err = 0;
        tc = NULL;
        rc = NULL;
        clnt = fid->clnt;
        total = 0;

        rsize = fid->iounit;
        if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
                rsize = clnt->msize - P9_IOHDRSZ;

        do {
                if (count < rsize)
                        rsize = count;

                tc = p9_create_twrite(fid->fid, offset, rsize, data);
                if (IS_ERR(tc)) {
                        err = PTR_ERR(tc);
                        tc = NULL;
                        goto error;
                }

                err = p9_client_rpc(clnt, tc, &rc);
                if (err)
                        goto error;

                n = rc->params.rread.count;
                count -= n;
                data += n;
                offset += n;
                total += n;
                kfree(tc);
                tc = NULL;
                kfree(rc);
                rc = NULL;
        } while (count > 0);

        return total;

error:
        kfree(tc);
        kfree(rc);
        return err;
}
EXPORT_SYMBOL(p9_client_write);

int
p9_client_uread(struct p9_fid *fid, char __user *data, u64 offset, u32 count)
{
        int err, n, rsize, total;
        struct p9_fcall *tc, *rc;
        struct p9_client *clnt;

        P9_DPRINTK(P9_DEBUG_9P, "fid %d offset %llu count %d\n", fid->fid,
                                        (long long unsigned) offset, count);
        err = 0;
        tc = NULL;
        rc = NULL;
        clnt = fid->clnt;
        total = 0;

        rsize = fid->iounit;
        if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
                rsize = clnt->msize - P9_IOHDRSZ;

        do {
                if (count < rsize)
                        rsize = count;

                tc = p9_create_tread(fid->fid, offset, rsize);
                if (IS_ERR(tc)) {
                        err = PTR_ERR(tc);
                        tc = NULL;
                        goto error;
                }

                err = p9_client_rpc(clnt, tc, &rc);
                if (err)
                        goto error;

                n = rc->params.rread.count;
                if (n > count)
                        n = count;

                err = copy_to_user(data, rc->params.rread.data, n);
                if (err) {
                        err = -EFAULT;
                        goto error;
                }

                count -= n;
                data += n;
                offset += n;
                total += n;
                kfree(tc);
                tc = NULL;
                kfree(rc);
                rc = NULL;
        } while (count > 0 && n == rsize);

        return total;

error:
        kfree(tc);
        kfree(rc);
        return err;
}
EXPORT_SYMBOL(p9_client_uread);

int
p9_client_uwrite(struct p9_fid *fid, const char __user *data, u64 offset,
                                                                   u32 count)
{
        int err, n, rsize, total;
        struct p9_fcall *tc, *rc;
        struct p9_client *clnt;

        P9_DPRINTK(P9_DEBUG_9P, "fid %d offset %llu count %d\n", fid->fid,
                                        (long long unsigned) offset, count);
        err = 0;
        tc = NULL;
        rc = NULL;
        clnt = fid->clnt;
        total = 0;

        rsize = fid->iounit;
        if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
                rsize = clnt->msize - P9_IOHDRSZ;

        do {
                if (count < rsize)
                        rsize = count;

                tc = p9_create_twrite_u(fid->fid, offset, rsize, data);
                if (IS_ERR(tc)) {
                        err = PTR_ERR(tc);
                        tc = NULL;
                        goto error;
                }

                err = p9_client_rpc(clnt, tc, &rc);
                if (err)
                        goto error;

                n = rc->params.rread.count;
                count -= n;
                data += n;
                offset += n;
                total += n;
                kfree(tc);
                tc = NULL;
                kfree(rc);
                rc = NULL;
        } while (count > 0);

        return total;

error:
        kfree(tc);
        kfree(rc);
        return err;
}
EXPORT_SYMBOL(p9_client_uwrite);

int p9_client_readn(struct p9_fid *fid, char *data, u64 offset, u32 count)
{
        int n, total;

        P9_DPRINTK(P9_DEBUG_9P, "fid %d offset %llu count %d\n", fid->fid,
                                        (long long unsigned) offset, count);
        n = 0;
        total = 0;
        while (count) {
                n = p9_client_read(fid, data, offset, count);
                if (n <= 0)
                        break;

                data += n;
                offset += n;
                count -= n;
                total += n;
        }

        if (n < 0)
                total = n;

        return total;
}
EXPORT_SYMBOL(p9_client_readn);

struct p9_stat *p9_client_stat(struct p9_fid *fid)
{
        int err;
        struct p9_fcall *tc, *rc;
        struct p9_client *clnt;
        struct p9_stat *ret;

        P9_DPRINTK(P9_DEBUG_9P, "fid %d\n", fid->fid);
        err = 0;
        tc = NULL;
        rc = NULL;
        ret = NULL;
        clnt = fid->clnt;

        tc = p9_create_tstat(fid->fid);
        if (IS_ERR(tc)) {
                err = PTR_ERR(tc);
                tc = NULL;
                goto error;
        }

        err = p9_client_rpc(clnt, tc, &rc);
        if (err)
                goto error;

        ret = p9_clone_stat(&rc->params.rstat.stat, clnt->dotu);
        if (IS_ERR(ret)) {
                err = PTR_ERR(ret);
                ret = NULL;
                goto error;
        }

        kfree(tc);
        kfree(rc);
        return ret;

error:
        kfree(tc);
        kfree(rc);
        kfree(ret);
        return ERR_PTR(err);
}
EXPORT_SYMBOL(p9_client_stat);

int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst)
{
        int err;
        struct p9_fcall *tc, *rc;
        struct p9_client *clnt;

        P9_DPRINTK(P9_DEBUG_9P, "fid %d\n", fid->fid);
        err = 0;
        tc = NULL;
        rc = NULL;
        clnt = fid->clnt;

        tc = p9_create_twstat(fid->fid, wst, clnt->dotu);
        if (IS_ERR(tc)) {
                err = PTR_ERR(tc);
                tc = NULL;
                goto done;
        }

        err = p9_client_rpc(clnt, tc, &rc);

done:
        kfree(tc);
        kfree(rc);
        return err;
}
EXPORT_SYMBOL(p9_client_wstat);

struct p9_stat *p9_client_dirread(struct p9_fid *fid, u64 offset)
{
        int err, n, m;
        struct p9_fcall *tc, *rc;
        struct p9_client *clnt;
        struct p9_stat st, *ret;

        P9_DPRINTK(P9_DEBUG_9P, "fid %d offset %llu\n", fid->fid,
                                                (long long unsigned) offset);
        err = 0;
        tc = NULL;
        rc = NULL;
        ret = NULL;
        clnt = fid->clnt;

        /* if the offset is below or above the current response, free it */
        if (offset < fid->rdir_fpos || (fid->rdir_fcall &&
                offset >= fid->rdir_fpos+fid->rdir_fcall->params.rread.count)) {
                fid->rdir_pos = 0;
                if (fid->rdir_fcall)
                        fid->rdir_fpos += fid->rdir_fcall->params.rread.count;

                kfree(fid->rdir_fcall);
                fid->rdir_fcall = NULL;
                if (offset < fid->rdir_fpos)
                        fid->rdir_fpos = 0;
        }

        if (!fid->rdir_fcall) {
                n = fid->iounit;
                if (!n || n > clnt->msize-P9_IOHDRSZ)
                        n = clnt->msize - P9_IOHDRSZ;

                while (1) {
                        if (fid->rdir_fcall) {
                                fid->rdir_fpos +=
                                        fid->rdir_fcall->params.rread.count;
                                kfree(fid->rdir_fcall);
                                fid->rdir_fcall = NULL;
                        }

                        tc = p9_create_tread(fid->fid, fid->rdir_fpos, n);
                        if (IS_ERR(tc)) {
                                err = PTR_ERR(tc);
                                tc = NULL;
                                goto error;
                        }

                        err = p9_client_rpc(clnt, tc, &rc);
                        if (err)
                                goto error;

                        n = rc->params.rread.count;
                        if (n == 0)
                                goto done;

                        fid->rdir_fcall = rc;
                        rc = NULL;
                        if (offset >= fid->rdir_fpos &&
                                                offset < fid->rdir_fpos+n)
                                break;
                }

                fid->rdir_pos = 0;
        }

        m = offset - fid->rdir_fpos;
        if (m < 0)
                goto done;

        n = p9_deserialize_stat(fid->rdir_fcall->params.rread.data + m,
                fid->rdir_fcall->params.rread.count - m, &st, clnt->dotu);

        if (!n) {
                err = -EIO;
                goto error;
        }

        fid->rdir_pos += n;
        st.size = n;
        ret = p9_clone_stat(&st, clnt->dotu);
        if (IS_ERR(ret)) {
                err = PTR_ERR(ret);
                ret = NULL;
                goto error;
        }

done:
        kfree(tc);
        kfree(rc);
        return ret;

error:
        kfree(tc);
        kfree(rc);
        kfree(ret);
        return ERR_PTR(err);
}
EXPORT_SYMBOL(p9_client_dirread);

static struct p9_stat *p9_clone_stat(struct p9_stat *st, int dotu)
{
        int n;
        char *p;
        struct p9_stat *ret;

        n = sizeof(struct p9_stat) + st->name.len + st->uid.len + st->gid.len +
                st->muid.len;

        if (dotu)
                n += st->extension.len;

        ret = kmalloc(n, GFP_KERNEL);
        if (!ret)
                return ERR_PTR(-ENOMEM);

        memmove(ret, st, sizeof(struct p9_stat));
        p = ((char *) ret) + sizeof(struct p9_stat);
        memmove(p, st->name.str, st->name.len);
        ret->name.str = p;
        p += st->name.len;
        memmove(p, st->uid.str, st->uid.len);
        ret->uid.str = p;
        p += st->uid.len;
        memmove(p, st->gid.str, st->gid.len);
        ret->gid.str = p;
        p += st->gid.len;
        memmove(p, st->muid.str, st->muid.len);
        ret->muid.str = p;
        p += st->muid.len;

        if (dotu) {
                memmove(p, st->extension.str, st->extension.len);
                ret->extension.str = p;
                p += st->extension.len;
        }

        return ret;
}

static struct p9_fid *p9_fid_create(struct p9_client *clnt)
{
        int err;
        struct p9_fid *fid;

        P9_DPRINTK(P9_DEBUG_9P, "clnt %p\n", clnt);
        fid = kmalloc(sizeof(struct p9_fid), GFP_KERNEL);
        if (!fid)
                return ERR_PTR(-ENOMEM);

        fid->fid = p9_idpool_get(clnt->fidpool);
        if (fid->fid < 0) {
                err = -ENOSPC;
                goto error;
        }

        memset(&fid->qid, 0, sizeof(struct p9_qid));
        fid->mode = -1;
        fid->rdir_fpos = 0;
        fid->rdir_pos = 0;
        fid->rdir_fcall = NULL;
        fid->uid = current->fsuid;
        fid->clnt = clnt;
        fid->aux = NULL;

        spin_lock(&clnt->lock);
        list_add(&fid->flist, &clnt->fidlist);
        spin_unlock(&clnt->lock);

        return fid;

error:
        kfree(fid);
        return ERR_PTR(err);
}

static void p9_fid_destroy(struct p9_fid *fid)
{
        struct p9_client *clnt;

        P9_DPRINTK(P9_DEBUG_9P, "fid %d\n", fid->fid);
        clnt = fid->clnt;
        p9_idpool_put(fid->fid, clnt->fidpool);
        spin_lock(&clnt->lock);
        list_del(&fid->flist);
        spin_unlock(&clnt->lock);
        kfree(fid->rdir_fcall);
        kfree(fid);
}

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