This commit was manufactured by cvs2svn to create branch 'vserver'.
[linux-2.6.git] / fs / 9p / conv.c
diff --git a/fs/9p/conv.c b/fs/9p/conv.c
new file mode 100644 (file)
index 0000000..a767e05
--- /dev/null
@@ -0,0 +1,843 @@
+/*
+ * linux/fs/9p/conv.c
+ *
+ * 9P protocol conversion functions
+ *
+ *  Copyright (C) 2004, 2005 by Latchesar Ionkov <lucho@ionkov.net>
+ *  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 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/config.h>
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/idr.h>
+#include <asm/uaccess.h>
+#include "debug.h"
+#include "v9fs.h"
+#include "9p.h"
+#include "conv.h"
+
+/*
+ * Buffer to help with string parsing
+ */
+struct cbuf {
+       unsigned char *sp;
+       unsigned char *p;
+       unsigned char *ep;
+};
+
+static inline void buf_init(struct cbuf *buf, void *data, int datalen)
+{
+       buf->sp = buf->p = data;
+       buf->ep = data + datalen;
+}
+
+static inline int buf_check_overflow(struct cbuf *buf)
+{
+       return buf->p > buf->ep;
+}
+
+static int buf_check_size(struct cbuf *buf, int len)
+{
+       if (buf->p + len > buf->ep) {
+               if (buf->p < buf->ep) {
+                       eprintk(KERN_ERR, "buffer overflow: want %d has %d\n",
+                               len, (int)(buf->ep - buf->p));
+                       dump_stack();
+                       buf->p = buf->ep + 1;
+               }
+
+               return 0;
+       }
+
+       return 1;
+}
+
+static void *buf_alloc(struct cbuf *buf, int len)
+{
+       void *ret = NULL;
+
+       if (buf_check_size(buf, len)) {
+               ret = buf->p;
+               buf->p += len;
+       }
+
+       return ret;
+}
+
+static void buf_put_int8(struct cbuf *buf, u8 val)
+{
+       if (buf_check_size(buf, 1)) {
+               buf->p[0] = val;
+               buf->p++;
+       }
+}
+
+static void buf_put_int16(struct cbuf *buf, u16 val)
+{
+       if (buf_check_size(buf, 2)) {
+               *(__le16 *) buf->p = cpu_to_le16(val);
+               buf->p += 2;
+       }
+}
+
+static void buf_put_int32(struct cbuf *buf, u32 val)
+{
+       if (buf_check_size(buf, 4)) {
+               *(__le32 *)buf->p = cpu_to_le32(val);
+               buf->p += 4;
+       }
+}
+
+static void buf_put_int64(struct cbuf *buf, u64 val)
+{
+       if (buf_check_size(buf, 8)) {
+               *(__le64 *)buf->p = cpu_to_le64(val);
+               buf->p += 8;
+       }
+}
+
+static char *buf_put_stringn(struct cbuf *buf, const char *s, u16 slen)
+{
+       char *ret;
+
+       ret = NULL;
+       if (buf_check_size(buf, slen + 2)) {
+               buf_put_int16(buf, slen);
+               ret = buf->p;
+               memcpy(buf->p, s, slen);
+               buf->p += slen;
+       }
+
+       return ret;
+}
+
+static inline void buf_put_string(struct cbuf *buf, const char *s)
+{
+       buf_put_stringn(buf, s, strlen(s));
+}
+
+static u8 buf_get_int8(struct cbuf *buf)
+{
+       u8 ret = 0;
+
+       if (buf_check_size(buf, 1)) {
+               ret = buf->p[0];
+               buf->p++;
+       }
+
+       return ret;
+}
+
+static u16 buf_get_int16(struct cbuf *buf)
+{
+       u16 ret = 0;
+
+       if (buf_check_size(buf, 2)) {
+               ret = le16_to_cpu(*(__le16 *)buf->p);
+               buf->p += 2;
+       }
+
+       return ret;
+}
+
+static u32 buf_get_int32(struct cbuf *buf)
+{
+       u32 ret = 0;
+
+       if (buf_check_size(buf, 4)) {
+               ret = le32_to_cpu(*(__le32 *)buf->p);
+               buf->p += 4;
+       }
+
+       return ret;
+}
+
+static u64 buf_get_int64(struct cbuf *buf)
+{
+       u64 ret = 0;
+
+       if (buf_check_size(buf, 8)) {
+               ret = le64_to_cpu(*(__le64 *)buf->p);
+               buf->p += 8;
+       }
+
+       return ret;
+}
+
+static void buf_get_str(struct cbuf *buf, struct v9fs_str *vstr)
+{
+       vstr->len = buf_get_int16(buf);
+       if (!buf_check_overflow(buf) && buf_check_size(buf, vstr->len)) {
+               vstr->str = buf->p;
+               buf->p += vstr->len;
+       } else {
+               vstr->len = 0;
+               vstr->str = NULL;
+       }
+}
+
+static void buf_get_qid(struct cbuf *bufp, struct v9fs_qid *qid)
+{
+       qid->type = buf_get_int8(bufp);
+       qid->version = buf_get_int32(bufp);
+       qid->path = buf_get_int64(bufp);
+}
+
+/**
+ * v9fs_size_wstat - calculate the size of a variable length stat struct
+ * @stat: metadata (stat) structure
+ * @extended: non-zero if 9P2000.u
+ *
+ */
+
+static int v9fs_size_wstat(struct v9fs_wstat *wstat, int extended)
+{
+       int size = 0;
+
+       if (wstat == NULL) {
+               eprintk(KERN_ERR, "v9fs_size_stat: got a NULL stat pointer\n");
+               return 0;
+       }
+
+       size =                  /* 2 + *//* size[2] */
+           2 +                 /* type[2] */
+           4 +                 /* dev[4] */
+           1 +                 /* qid.type[1] */
+           4 +                 /* qid.vers[4] */
+           8 +                 /* qid.path[8] */
+           4 +                 /* mode[4] */
+           4 +                 /* atime[4] */
+           4 +                 /* mtime[4] */
+           8 +                 /* length[8] */
+           8;                  /* minimum sum of string lengths */
+
+       if (wstat->name)
+               size += strlen(wstat->name);
+       if (wstat->uid)
+               size += strlen(wstat->uid);
+       if (wstat->gid)
+               size += strlen(wstat->gid);
+       if (wstat->muid)
+               size += strlen(wstat->muid);
+
+       if (extended) {
+               size += 4 +     /* n_uid[4] */
+                   4 +         /* n_gid[4] */
+                   4 +         /* n_muid[4] */
+                   2;          /* string length of extension[4] */
+               if (wstat->extension)
+                       size += strlen(wstat->extension);
+       }
+
+       return size;
+}
+
+/**
+ * buf_get_stat - safely decode a recieved metadata (stat) structure
+ * @bufp: buffer to deserialize
+ * @stat: metadata (stat) structure
+ * @extended: non-zero if 9P2000.u
+ *
+ */
+
+static void
+buf_get_stat(struct cbuf *bufp, struct v9fs_stat *stat, int extended)
+{
+       stat->size = buf_get_int16(bufp);
+       stat->type = buf_get_int16(bufp);
+       stat->dev = buf_get_int32(bufp);
+       stat->qid.type = buf_get_int8(bufp);
+       stat->qid.version = buf_get_int32(bufp);
+       stat->qid.path = buf_get_int64(bufp);
+       stat->mode = buf_get_int32(bufp);
+       stat->atime = buf_get_int32(bufp);
+       stat->mtime = buf_get_int32(bufp);
+       stat->length = buf_get_int64(bufp);
+       buf_get_str(bufp, &stat->name);
+       buf_get_str(bufp, &stat->uid);
+       buf_get_str(bufp, &stat->gid);
+       buf_get_str(bufp, &stat->muid);
+
+       if (extended) {
+               buf_get_str(bufp, &stat->extension);
+               stat->n_uid = buf_get_int32(bufp);
+               stat->n_gid = buf_get_int32(bufp);
+               stat->n_muid = buf_get_int32(bufp);
+       }
+}
+
+/**
+ * v9fs_deserialize_stat - decode a received metadata structure
+ * @buf: buffer to deserialize
+ * @buflen: length of received buffer
+ * @stat: metadata structure to decode into
+ * @extended: non-zero if 9P2000.u
+ *
+ * Note: stat will point to the buf region.
+ */
+
+int
+v9fs_deserialize_stat(void *buf, u32 buflen, struct v9fs_stat *stat,
+               int extended)
+{
+       struct cbuf buffer;
+       struct cbuf *bufp = &buffer;
+       unsigned char *p;
+
+       buf_init(bufp, buf, buflen);
+       p = bufp->p;
+       buf_get_stat(bufp, stat, extended);
+
+       if (buf_check_overflow(bufp))
+               return 0;
+       else
+               return bufp->p - p;
+}
+
+/**
+ * deserialize_fcall - unmarshal a response
+ * @buf: recieved buffer
+ * @buflen: length of received buffer
+ * @rcall: fcall structure to populate
+ * @rcalllen: length of fcall structure to populate
+ * @extended: non-zero if 9P2000.u
+ *
+ */
+
+int
+v9fs_deserialize_fcall(void *buf, u32 buflen, struct v9fs_fcall *rcall,
+                      int extended)
+{
+
+       struct cbuf buffer;
+       struct cbuf *bufp = &buffer;
+       int i = 0;
+
+       buf_init(bufp, buf, buflen);
+
+       rcall->size = buf_get_int32(bufp);
+       rcall->id = buf_get_int8(bufp);
+       rcall->tag = buf_get_int16(bufp);
+
+       dprintk(DEBUG_CONV, "size %d id %d tag %d\n", rcall->size, rcall->id,
+               rcall->tag);
+
+       switch (rcall->id) {
+       default:
+               eprintk(KERN_ERR, "unknown message type: %d\n", rcall->id);
+               return -EPROTO;
+       case RVERSION:
+               rcall->params.rversion.msize = buf_get_int32(bufp);
+               buf_get_str(bufp, &rcall->params.rversion.version);
+               break;
+       case RFLUSH:
+               break;
+       case RATTACH:
+               rcall->params.rattach.qid.type = buf_get_int8(bufp);
+               rcall->params.rattach.qid.version = buf_get_int32(bufp);
+               rcall->params.rattach.qid.path = buf_get_int64(bufp);
+               break;
+       case RWALK:
+               rcall->params.rwalk.nwqid = buf_get_int16(bufp);
+               if (rcall->params.rwalk.nwqid > V9FS_MAXWELEM) {
+                       eprintk(KERN_ERR, "Rwalk with more than %d qids: %d\n",
+                               V9FS_MAXWELEM, rcall->params.rwalk.nwqid);
+                       return -EPROTO;
+               }
+
+               for (i = 0; i < rcall->params.rwalk.nwqid; i++)
+                       buf_get_qid(bufp, &rcall->params.rwalk.wqids[i]);
+               break;
+       case ROPEN:
+               buf_get_qid(bufp, &rcall->params.ropen.qid);
+               rcall->params.ropen.iounit = buf_get_int32(bufp);
+               break;
+       case RCREATE:
+               buf_get_qid(bufp, &rcall->params.rcreate.qid);
+               rcall->params.rcreate.iounit = buf_get_int32(bufp);
+               break;
+       case RREAD:
+               rcall->params.rread.count = buf_get_int32(bufp);
+               rcall->params.rread.data = bufp->p;
+               buf_check_size(bufp, rcall->params.rread.count);
+               break;
+       case RWRITE:
+               rcall->params.rwrite.count = buf_get_int32(bufp);
+               break;
+       case RCLUNK:
+               break;
+       case RREMOVE:
+               break;
+       case RSTAT:
+               buf_get_int16(bufp);
+               buf_get_stat(bufp, &rcall->params.rstat.stat, extended);
+               break;
+       case RWSTAT:
+               break;
+       case RERROR:
+               buf_get_str(bufp, &rcall->params.rerror.error);
+               if (extended)
+                       rcall->params.rerror.errno = buf_get_int16(bufp);
+               break;
+       }
+
+       if (buf_check_overflow(bufp)) {
+               dprintk(DEBUG_ERROR, "buffer overflow\n");
+               return -EIO;
+       }
+
+       return bufp->p - bufp->sp;
+}
+
+static inline void v9fs_put_int8(struct cbuf *bufp, u8 val, u8 * p)
+{
+       *p = val;
+       buf_put_int8(bufp, val);
+}
+
+static inline void v9fs_put_int16(struct cbuf *bufp, u16 val, u16 * p)
+{
+       *p = val;
+       buf_put_int16(bufp, val);
+}
+
+static inline void v9fs_put_int32(struct cbuf *bufp, u32 val, u32 * p)
+{
+       *p = val;
+       buf_put_int32(bufp, val);
+}
+
+static inline void v9fs_put_int64(struct cbuf *bufp, u64 val, u64 * p)
+{
+       *p = val;
+       buf_put_int64(bufp, val);
+}
+
+static void
+v9fs_put_str(struct cbuf *bufp, char *data, struct v9fs_str *str)
+{
+       int len;
+       char *s;
+
+       if (data)
+               len = strlen(data);
+       else
+               len = 0;
+
+       s = buf_put_stringn(bufp, data, len);
+       if (str) {
+               str->len = len;
+               str->str = s;
+       }
+}
+
+static int
+v9fs_put_user_data(struct cbuf *bufp, const char __user * data, int count,
+                  unsigned char **pdata)
+{
+       *pdata = buf_alloc(bufp, count);
+       return copy_from_user(*pdata, data, count);
+}
+
+static void
+v9fs_put_wstat(struct cbuf *bufp, struct v9fs_wstat *wstat,
+              struct v9fs_stat *stat, int statsz, int extended)
+{
+       v9fs_put_int16(bufp, statsz, &stat->size);
+       v9fs_put_int16(bufp, wstat->type, &stat->type);
+       v9fs_put_int32(bufp, wstat->dev, &stat->dev);
+       v9fs_put_int8(bufp, wstat->qid.type, &stat->qid.type);
+       v9fs_put_int32(bufp, wstat->qid.version, &stat->qid.version);
+       v9fs_put_int64(bufp, wstat->qid.path, &stat->qid.path);
+       v9fs_put_int32(bufp, wstat->mode, &stat->mode);
+       v9fs_put_int32(bufp, wstat->atime, &stat->atime);
+       v9fs_put_int32(bufp, wstat->mtime, &stat->mtime);
+       v9fs_put_int64(bufp, wstat->length, &stat->length);
+
+       v9fs_put_str(bufp, wstat->name, &stat->name);
+       v9fs_put_str(bufp, wstat->uid, &stat->uid);
+       v9fs_put_str(bufp, wstat->gid, &stat->gid);
+       v9fs_put_str(bufp, wstat->muid, &stat->muid);
+
+       if (extended) {
+               v9fs_put_str(bufp, wstat->extension, &stat->extension);
+               v9fs_put_int32(bufp, wstat->n_uid, &stat->n_uid);
+               v9fs_put_int32(bufp, wstat->n_gid, &stat->n_gid);
+               v9fs_put_int32(bufp, wstat->n_muid, &stat->n_muid);
+       }
+}
+
+static struct v9fs_fcall *
+v9fs_create_common(struct cbuf *bufp, u32 size, u8 id)
+{
+       struct v9fs_fcall *fc;
+
+       size += 4 + 1 + 2;      /* size[4] id[1] tag[2] */
+       fc = kmalloc(sizeof(struct v9fs_fcall) + size, GFP_KERNEL);
+       if (!fc)
+               return ERR_PTR(-ENOMEM);
+
+       fc->sdata = (char *)fc + sizeof(*fc);
+
+       buf_init(bufp, (char *)fc->sdata, size);
+       v9fs_put_int32(bufp, size, &fc->size);
+       v9fs_put_int8(bufp, id, &fc->id);
+       v9fs_put_int16(bufp, V9FS_NOTAG, &fc->tag);
+
+       return fc;
+}
+
+void v9fs_set_tag(struct v9fs_fcall *fc, u16 tag)
+{
+       fc->tag = tag;
+       *(__le16 *) (fc->sdata + 5) = cpu_to_le16(tag);
+}
+
+struct v9fs_fcall *v9fs_create_tversion(u32 msize, char *version)
+{
+       int size;
+       struct v9fs_fcall *fc;
+       struct cbuf buffer;
+       struct cbuf *bufp = &buffer;
+
+       size = 4 + 2 + strlen(version); /* msize[4] version[s] */
+       fc = v9fs_create_common(bufp, size, TVERSION);
+       if (IS_ERR(fc))
+               goto error;
+
+       v9fs_put_int32(bufp, msize, &fc->params.tversion.msize);
+       v9fs_put_str(bufp, version, &fc->params.tversion.version);
+
+       if (buf_check_overflow(bufp)) {
+               kfree(fc);
+               fc = ERR_PTR(-ENOMEM);
+       }
+      error:
+       return fc;
+}
+
+#if 0
+struct v9fs_fcall *v9fs_create_tauth(u32 afid, char *uname, char *aname)
+{
+       int size;
+       struct v9fs_fcall *fc;
+       struct cbuf buffer;
+       struct cbuf *bufp = &buffer;
+
+       size = 4 + 2 + strlen(uname) + 2 + strlen(aname);       /* afid[4] uname[s] aname[s] */
+       fc = v9fs_create_common(bufp, size, TAUTH);
+       if (IS_ERR(fc))
+               goto error;
+
+       v9fs_put_int32(bufp, afid, &fc->params.tauth.afid);
+       v9fs_put_str(bufp, uname, &fc->params.tauth.uname);
+       v9fs_put_str(bufp, aname, &fc->params.tauth.aname);
+
+       if (buf_check_overflow(bufp)) {
+               kfree(fc);
+               fc = ERR_PTR(-ENOMEM);
+       }
+      error:
+       return fc;
+}
+#endif  /*  0  */
+
+struct v9fs_fcall *
+v9fs_create_tattach(u32 fid, u32 afid, char *uname, char *aname)
+{
+       int size;
+       struct v9fs_fcall *fc;
+       struct cbuf buffer;
+       struct cbuf *bufp = &buffer;
+
+       size = 4 + 4 + 2 + strlen(uname) + 2 + strlen(aname);   /* fid[4] afid[4] uname[s] aname[s] */
+       fc = v9fs_create_common(bufp, size, TATTACH);
+       if (IS_ERR(fc))
+               goto error;
+
+       v9fs_put_int32(bufp, fid, &fc->params.tattach.fid);
+       v9fs_put_int32(bufp, afid, &fc->params.tattach.afid);
+       v9fs_put_str(bufp, uname, &fc->params.tattach.uname);
+       v9fs_put_str(bufp, aname, &fc->params.tattach.aname);
+
+      error:
+       return fc;
+}
+
+struct v9fs_fcall *v9fs_create_tflush(u16 oldtag)
+{
+       int size;
+       struct v9fs_fcall *fc;
+       struct cbuf buffer;
+       struct cbuf *bufp = &buffer;
+
+       size = 2;               /* oldtag[2] */
+       fc = v9fs_create_common(bufp, size, TFLUSH);
+       if (IS_ERR(fc))
+               goto error;
+
+       v9fs_put_int16(bufp, oldtag, &fc->params.tflush.oldtag);
+
+       if (buf_check_overflow(bufp)) {
+               kfree(fc);
+               fc = ERR_PTR(-ENOMEM);
+       }
+      error:
+       return fc;
+}
+
+struct v9fs_fcall *v9fs_create_twalk(u32 fid, u32 newfid, u16 nwname,
+                                    char **wnames)
+{
+       int i, size;
+       struct v9fs_fcall *fc;
+       struct cbuf buffer;
+       struct cbuf *bufp = &buffer;
+
+       if (nwname > V9FS_MAXWELEM) {
+               dprintk(DEBUG_ERROR, "nwname > %d\n", V9FS_MAXWELEM);
+               return NULL;
+       }
+
+       size = 4 + 4 + 2;       /* fid[4] newfid[4] nwname[2] ... */
+       for (i = 0; i < nwname; i++) {
+               size += 2 + strlen(wnames[i]);  /* wname[s] */
+       }
+
+       fc = v9fs_create_common(bufp, size, TWALK);
+       if (IS_ERR(fc))
+               goto error;
+
+       v9fs_put_int32(bufp, fid, &fc->params.twalk.fid);
+       v9fs_put_int32(bufp, newfid, &fc->params.twalk.newfid);
+       v9fs_put_int16(bufp, nwname, &fc->params.twalk.nwname);
+       for (i = 0; i < nwname; i++) {
+               v9fs_put_str(bufp, wnames[i], &fc->params.twalk.wnames[i]);
+       }
+
+       if (buf_check_overflow(bufp)) {
+               kfree(fc);
+               fc = ERR_PTR(-ENOMEM);
+       }
+      error:
+       return fc;
+}
+
+struct v9fs_fcall *v9fs_create_topen(u32 fid, u8 mode)
+{
+       int size;
+       struct v9fs_fcall *fc;
+       struct cbuf buffer;
+       struct cbuf *bufp = &buffer;
+
+       size = 4 + 1;           /* fid[4] mode[1] */
+       fc = v9fs_create_common(bufp, size, TOPEN);
+       if (IS_ERR(fc))
+               goto error;
+
+       v9fs_put_int32(bufp, fid, &fc->params.topen.fid);
+       v9fs_put_int8(bufp, mode, &fc->params.topen.mode);
+
+       if (buf_check_overflow(bufp)) {
+               kfree(fc);
+               fc = ERR_PTR(-ENOMEM);
+       }
+      error:
+       return fc;
+}
+
+struct v9fs_fcall *v9fs_create_tcreate(u32 fid, char *name, u32 perm, u8 mode,
+       char *extension, int extended)
+{
+       int size;
+       struct v9fs_fcall *fc;
+       struct cbuf buffer;
+       struct cbuf *bufp = &buffer;
+
+       size = 4 + 2 + strlen(name) + 4 + 1;    /* fid[4] name[s] perm[4] mode[1] */
+       if (extended && extension!=NULL)
+               size += 2 + strlen(extension);  /* extension[s] */
+
+       fc = v9fs_create_common(bufp, size, TCREATE);
+       if (IS_ERR(fc))
+               goto error;
+
+       v9fs_put_int32(bufp, fid, &fc->params.tcreate.fid);
+       v9fs_put_str(bufp, name, &fc->params.tcreate.name);
+       v9fs_put_int32(bufp, perm, &fc->params.tcreate.perm);
+       v9fs_put_int8(bufp, mode, &fc->params.tcreate.mode);
+       if (extended)
+               v9fs_put_str(bufp, extension, &fc->params.tcreate.extension);
+
+       if (buf_check_overflow(bufp)) {
+               kfree(fc);
+               fc = ERR_PTR(-ENOMEM);
+       }
+      error:
+       return fc;
+}
+
+struct v9fs_fcall *v9fs_create_tread(u32 fid, u64 offset, u32 count)
+{
+       int size;
+       struct v9fs_fcall *fc;
+       struct cbuf buffer;
+       struct cbuf *bufp = &buffer;
+
+       size = 4 + 8 + 4;       /* fid[4] offset[8] count[4] */
+       fc = v9fs_create_common(bufp, size, TREAD);
+       if (IS_ERR(fc))
+               goto error;
+
+       v9fs_put_int32(bufp, fid, &fc->params.tread.fid);
+       v9fs_put_int64(bufp, offset, &fc->params.tread.offset);
+       v9fs_put_int32(bufp, count, &fc->params.tread.count);
+
+       if (buf_check_overflow(bufp)) {
+               kfree(fc);
+               fc = ERR_PTR(-ENOMEM);
+       }
+      error:
+       return fc;
+}
+
+struct v9fs_fcall *v9fs_create_twrite(u32 fid, u64 offset, u32 count,
+                                     const char __user * data)
+{
+       int size, err;
+       struct v9fs_fcall *fc;
+       struct cbuf buffer;
+       struct cbuf *bufp = &buffer;
+
+       size = 4 + 8 + 4 + count;       /* fid[4] offset[8] count[4] data[count] */
+       fc = v9fs_create_common(bufp, size, TWRITE);
+       if (IS_ERR(fc))
+               goto error;
+
+       v9fs_put_int32(bufp, fid, &fc->params.twrite.fid);
+       v9fs_put_int64(bufp, offset, &fc->params.twrite.offset);
+       v9fs_put_int32(bufp, count, &fc->params.twrite.count);
+       err = v9fs_put_user_data(bufp, data, count, &fc->params.twrite.data);
+       if (err) {
+               kfree(fc);
+               fc = ERR_PTR(err);
+       }
+
+       if (buf_check_overflow(bufp)) {
+               kfree(fc);
+               fc = ERR_PTR(-ENOMEM);
+       }
+      error:
+       return fc;
+}
+
+struct v9fs_fcall *v9fs_create_tclunk(u32 fid)
+{
+       int size;
+       struct v9fs_fcall *fc;
+       struct cbuf buffer;
+       struct cbuf *bufp = &buffer;
+
+       size = 4;               /* fid[4] */
+       fc = v9fs_create_common(bufp, size, TCLUNK);
+       if (IS_ERR(fc))
+               goto error;
+
+       v9fs_put_int32(bufp, fid, &fc->params.tclunk.fid);
+
+       if (buf_check_overflow(bufp)) {
+               kfree(fc);
+               fc = ERR_PTR(-ENOMEM);
+       }
+      error:
+       return fc;
+}
+
+struct v9fs_fcall *v9fs_create_tremove(u32 fid)
+{
+       int size;
+       struct v9fs_fcall *fc;
+       struct cbuf buffer;
+       struct cbuf *bufp = &buffer;
+
+       size = 4;               /* fid[4] */
+       fc = v9fs_create_common(bufp, size, TREMOVE);
+       if (IS_ERR(fc))
+               goto error;
+
+       v9fs_put_int32(bufp, fid, &fc->params.tremove.fid);
+
+       if (buf_check_overflow(bufp)) {
+               kfree(fc);
+               fc = ERR_PTR(-ENOMEM);
+       }
+      error:
+       return fc;
+}
+
+struct v9fs_fcall *v9fs_create_tstat(u32 fid)
+{
+       int size;
+       struct v9fs_fcall *fc;
+       struct cbuf buffer;
+       struct cbuf *bufp = &buffer;
+
+       size = 4;               /* fid[4] */
+       fc = v9fs_create_common(bufp, size, TSTAT);
+       if (IS_ERR(fc))
+               goto error;
+
+       v9fs_put_int32(bufp, fid, &fc->params.tstat.fid);
+
+       if (buf_check_overflow(bufp)) {
+               kfree(fc);
+               fc = ERR_PTR(-ENOMEM);
+       }
+      error:
+       return fc;
+}
+
+struct v9fs_fcall *v9fs_create_twstat(u32 fid, struct v9fs_wstat *wstat,
+                                     int extended)
+{
+       int size, statsz;
+       struct v9fs_fcall *fc;
+       struct cbuf buffer;
+       struct cbuf *bufp = &buffer;
+
+       statsz = v9fs_size_wstat(wstat, extended);
+       size = 4 + 2 + 2 + statsz;      /* fid[4] stat[n] */
+       fc = v9fs_create_common(bufp, size, TWSTAT);
+       if (IS_ERR(fc))
+               goto error;
+
+       v9fs_put_int32(bufp, fid, &fc->params.twstat.fid);
+       buf_put_int16(bufp, statsz + 2);
+       v9fs_put_wstat(bufp, wstat, &fc->params.twstat.stat, statsz, extended);
+
+       if (buf_check_overflow(bufp)) {
+               kfree(fc);
+               fc = ERR_PTR(-ENOMEM);
+       }
+      error:
+       return fc;
+}