Merge remote-tracking branch 'aneesh/for-upstream' into staging

* aneesh/for-upstream:
  hw/9pfs: Add support to use named socket for proxy FS
  hw/9pfs: man page for proxy helper
  hw/9pfs: Documentation changes related to proxy fs
  hw/9pfs: Proxy getversion
  hw/9pfs: xattr interfaces in proxy filesystem driver
  hw/9pfs: File ownership and others
  hw/9pfs: Add stat/readlink/statfs for proxy FS
  hw/9pfs: Create other filesystem objects
  hw/9pfs: Open and create files
  hw/9pfs: File system helper process for qemu 9p proxy FS
  hw/9pfs: Add new proxy filesystem driver
  hw/9pfs: Add validation to {un}marshal code
  hw/9pfs: Move pdu_marshal/unmarshal code to a seperate file
  hw/9pfs: Move opt validation to FsDriver callback

7 files changed, 1713 insertions, 446 deletions

diff --git a/hw/9pfs/virtio-9p-device.c b/hw/9pfs/virtio-9p-device.c
index cd343e1d81..642d5e2c46 100644
--- a/hw/9pfs/virtio-9p-device.c
+++ b/hw/9pfs/virtio-9p-device.c
@@ -77,16 +77,19 @@ VirtIODevice *virtio_9p_init(DeviceState *dev, V9fsConf *conf)
         exit(1);
     }
 
-    if (!fse->path || !conf->tag) {
-        /* we haven't specified a mount_tag or the path */
-        fprintf(stderr, "fsdev with id %s needs path "
-                "and Virtio-9p device needs mount_tag arguments\n",
+    if (!conf->tag) {
+        /* we haven't specified a mount_tag */
+        fprintf(stderr, "fsdev with id %s needs mount_tag arguments\n",
                 conf->fsdev_id);
         exit(1);
     }
 
     s->ctx.export_flags = fse->export_flags;
-    s->ctx.fs_root = g_strdup(fse->path);
+    if (fse->path) {
+        s->ctx.fs_root = g_strdup(fse->path);
+    } else {
+        s->ctx.fs_root = NULL;
+    }
     s->ctx.exops.get_st_gen = NULL;
 
     if (fse->export_flags & V9FS_SM_PASSTHROUGH) {
diff --git a/hw/9pfs/virtio-9p-handle.c b/hw/9pfs/virtio-9p-handle.c
index b556e39702..cb012c0510 100644
--- a/hw/9pfs/virtio-9p-handle.c
+++ b/hw/9pfs/virtio-9p-handle.c
@@ -641,7 +641,27 @@ out:
     return ret;
 }
 
+static int handle_parse_opts(QemuOpts *opts, struct FsDriverEntry *fse)
+{
+    const char *sec_model = qemu_opt_get(opts, "security_model");
+    const char *path = qemu_opt_get(opts, "path");
+
+    if (sec_model) {
+        fprintf(stderr, "Invalid argument security_model specified with handle fsdriver\n");
+        return -1;
+    }
+
+    if (!path) {
+        fprintf(stderr, "fsdev: No path specified.\n");
+        return -1;
+    }
+    fse->path = g_strdup(path);
+    return 0;
+
+}
+
 FileOperations handle_ops = {
+    .parse_opts   = handle_parse_opts,
     .init         = handle_init,
     .lstat        = handle_lstat,
     .readlink     = handle_readlink,
diff --git a/hw/9pfs/virtio-9p-local.c b/hw/9pfs/virtio-9p-local.c
index 371a94dfff..3ae6ef2e39 100644
--- a/hw/9pfs/virtio-9p-local.c
+++ b/hw/9pfs/virtio-9p-local.c
@@ -756,7 +756,41 @@ static int local_init(FsContext *ctx)
     return err;
 }
 
+static int local_parse_opts(QemuOpts *opts, struct FsDriverEntry *fse)
+{
+    const char *sec_model = qemu_opt_get(opts, "security_model");
+    const char *path = qemu_opt_get(opts, "path");
+
+    if (!sec_model) {
+        fprintf(stderr, "security model not specified, "
+                "local fs needs security model\nvalid options are:"
+                "\tsecurity_model=[passthrough|mapped|none]\n");
+        return -1;
+    }
+
+    if (!strcmp(sec_model, "passthrough")) {
+        fse->export_flags |= V9FS_SM_PASSTHROUGH;
+    } else if (!strcmp(sec_model, "mapped")) {
+        fse->export_flags |= V9FS_SM_MAPPED;
+    } else if (!strcmp(sec_model, "none")) {
+        fse->export_flags |= V9FS_SM_NONE;
+    } else {
+        fprintf(stderr, "Invalid security model %s specified, valid options are"
+                "\n\t [passthrough|mapped|none]\n", sec_model);
+        return -1;
+    }
+
+    if (!path) {
+        fprintf(stderr, "fsdev: No path specified.\n");
+        return -1;
+    }
+    fse->path = g_strdup(path);
+
+    return 0;
+}
+
 FileOperations local_ops = {
+    .parse_opts = local_parse_opts,
     .init  = local_init,
     .lstat = local_lstat,
     .readlink = local_readlink,
diff --git a/hw/9pfs/virtio-9p-proxy.c b/hw/9pfs/virtio-9p-proxy.c
new file mode 100644
index 0000000000..44f5fc4f7e
--- /dev/null
+++ b/hw/9pfs/virtio-9p-proxy.c
@@ -0,0 +1,1210 @@
+/*
+ * Virtio 9p Proxy callback
+ *
+ * Copyright IBM, Corp. 2011
+ *
+ * Authors:
+ * M. Mohan Kumar <mohan@in.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ */
+#include <sys/socket.h>
+#include <sys/un.h>
+#include "hw/virtio.h"
+#include "virtio-9p.h"
+#include "fsdev/qemu-fsdev.h"
+#include "virtio-9p-proxy.h"
+
+typedef struct V9fsProxy {
+    int sockfd;
+    QemuMutex mutex;
+    struct iovec in_iovec;
+    struct iovec out_iovec;
+} V9fsProxy;
+
+/*
+ * Return received file descriptor on success in *status.
+ * errno is also returned on *status (which will be < 0)
+ * return < 0 on transport error.
+ */
+static int v9fs_receivefd(int sockfd, int *status)
+{
+    struct iovec iov;
+    struct msghdr msg;
+    struct cmsghdr *cmsg;
+    int retval, data, fd;
+    union MsgControl msg_control;
+
+    iov.iov_base = &data;
+    iov.iov_len = sizeof(data);
+
+    memset(&msg, 0, sizeof(msg));
+    msg.msg_iov = &iov;
+    msg.msg_iovlen = 1;
+    msg.msg_control = &msg_control;
+    msg.msg_controllen = sizeof(msg_control);
+
+    do {
+        retval = recvmsg(sockfd, &msg, 0);
+    } while (retval < 0 && errno == EINTR);
+    if (retval <= 0) {
+        return retval;
+    }
+    /*
+     * data is set to V9FS_FD_VALID, if ancillary data is sent.  If this
+     * request doesn't need ancillary data (fd) or an error occurred,
+     * data is set to negative errno value.
+     */
+    if (data != V9FS_FD_VALID) {
+        *status = data;
+        return 0;
+    }
+    /*
+     * File descriptor (fd) is sent in the ancillary data. Check if we
+     * indeed received it. One of the reasons to fail to receive it is if
+     * we exceeded the maximum number of file descriptors!
+     */
+    for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
+        if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)) ||
+            cmsg->cmsg_level != SOL_SOCKET ||
+            cmsg->cmsg_type != SCM_RIGHTS) {
+            continue;
+        }
+        fd = *((int *)CMSG_DATA(cmsg));
+        *status = fd;
+        return 0;
+    }
+    *status = -ENFILE;  /* Ancillary data sent but not received */
+    return 0;
+}
+
+static ssize_t socket_read(int sockfd, void *buff, size_t size)
+{
+    ssize_t retval, total = 0;
+
+    while (size) {
+        retval = read(sockfd, buff, size);
+        if (retval == 0) {
+            return -EIO;
+        }
+        if (retval < 0) {
+            if (errno == EINTR) {
+                continue;
+            }
+            return -errno;
+        }
+        size -= retval;
+        buff += retval;
+        total += retval;
+    }
+    return total;
+}
+
+/* Converts proxy_statfs to VFS statfs structure */
+static void prstatfs_to_statfs(struct statfs *stfs, ProxyStatFS *prstfs)
+{
+    memset(stfs, 0, sizeof(*stfs));
+    stfs->f_type = prstfs->f_type;
+    stfs->f_bsize = prstfs->f_bsize;
+    stfs->f_blocks = prstfs->f_blocks;
+    stfs->f_bfree = prstfs->f_bfree;
+    stfs->f_bavail = prstfs->f_bavail;
+    stfs->f_files = prstfs->f_files;
+    stfs->f_ffree = prstfs->f_ffree;
+    stfs->f_fsid.__val[0] = prstfs->f_fsid[0] & 0xFFFFFFFFUL;
+    stfs->f_fsid.__val[1] = prstfs->f_fsid[1] >> 32 & 0xFFFFFFFFFUL;
+    stfs->f_namelen = prstfs->f_namelen;
+    stfs->f_frsize = prstfs->f_frsize;
+}
+
+/* Converts proxy_stat structure to VFS stat structure */
+static void prstat_to_stat(struct stat *stbuf, ProxyStat *prstat)
+{
+   memset(stbuf, 0, sizeof(*stbuf));
+   stbuf->st_dev = prstat->st_dev;
+   stbuf->st_ino = prstat->st_ino;
+   stbuf->st_nlink = prstat->st_nlink;
+   stbuf->st_mode = prstat->st_mode;
+   stbuf->st_uid = prstat->st_uid;
+   stbuf->st_gid = prstat->st_gid;
+   stbuf->st_rdev = prstat->st_rdev;
+   stbuf->st_size = prstat->st_size;
+   stbuf->st_blksize = prstat->st_blksize;
+   stbuf->st_blocks = prstat->st_blocks;
+   stbuf->st_atim.tv_sec = prstat->st_atim_sec;
+   stbuf->st_atim.tv_nsec = prstat->st_atim_nsec;
+   stbuf->st_mtime = prstat->st_mtim_sec;
+   stbuf->st_mtim.tv_nsec = prstat->st_mtim_nsec;
+   stbuf->st_ctime = prstat->st_ctim_sec;
+   stbuf->st_ctim.tv_nsec = prstat->st_ctim_nsec;
+}
+
+/*
+ * Response contains two parts
+ * {header, data}
+ * header.type == T_ERROR, data -> -errno
+ * header.type == T_SUCCESS, data -> response
+ * size of errno/response is given by header.size
+ * returns < 0, on transport error. response is
+ * valid only if status >= 0.
+ */
+static int v9fs_receive_response(V9fsProxy *proxy, int type,
+                                 int *status, void *response)
+{
+    int retval;
+    ProxyHeader header;
+    struct iovec *reply = &proxy->in_iovec;
+
+    *status = 0;
+    reply->iov_len = 0;
+    retval = socket_read(proxy->sockfd, reply->iov_base, PROXY_HDR_SZ);
+    if (retval < 0) {
+        return retval;
+    }
+    reply->iov_len = PROXY_HDR_SZ;
+    proxy_unmarshal(reply, 0, "dd", &header.type, &header.size);
+    /*
+     * if response size > PROXY_MAX_IO_SZ, read the response but ignore it and
+     * return -ENOBUFS
+     */
+    if (header.size > PROXY_MAX_IO_SZ) {
+        int count;
+        while (header.size > 0) {
+            count = MIN(PROXY_MAX_IO_SZ, header.size);
+            count = socket_read(proxy->sockfd, reply->iov_base, count);
+            if (count < 0) {
+                return count;
+            }
+            header.size -= count;
+        }
+        *status = -ENOBUFS;
+        return 0;
+    }
+
+    retval = socket_read(proxy->sockfd,
+                         reply->iov_base + PROXY_HDR_SZ, header.size);
+    if (retval < 0) {
+        return retval;
+    }
+    reply->iov_len += header.size;
+    /* there was an error during processing request */
+    if (header.type == T_ERROR) {
+        int ret;
+        ret = proxy_unmarshal(reply, PROXY_HDR_SZ, "d", status);
+        if (ret < 0) {
+            *status = ret;
+        }
+        return 0;
+    }
+
+    switch (type) {
+    case T_LSTAT: {
+        ProxyStat prstat;
+        retval = proxy_unmarshal(reply, PROXY_HDR_SZ,
+                                 "qqqdddqqqqqqqqqq", &prstat.st_dev,
+                                 &prstat.st_ino, &prstat.st_nlink,
+                                 &prstat.st_mode, &prstat.st_uid,
+                                 &prstat.st_gid, &prstat.st_rdev,
+                                 &prstat.st_size, &prstat.st_blksize,
+                                 &prstat.st_blocks,
+                                 &prstat.st_atim_sec, &prstat.st_atim_nsec,
+                                 &prstat.st_mtim_sec, &prstat.st_mtim_nsec,
+                                 &prstat.st_ctim_sec, &prstat.st_ctim_nsec);
+        prstat_to_stat(response, &prstat);
+        break;
+    }
+    case T_STATFS: {
+        ProxyStatFS prstfs;
+        retval = proxy_unmarshal(reply, PROXY_HDR_SZ,
+                                 "qqqqqqqqqqq", &prstfs.f_type,
+                                 &prstfs.f_bsize, &prstfs.f_blocks,
+                                 &prstfs.f_bfree, &prstfs.f_bavail,
+                                 &prstfs.f_files, &prstfs.f_ffree,
+                                 &prstfs.f_fsid[0], &prstfs.f_fsid[1],
+                                 &prstfs.f_namelen, &prstfs.f_frsize);
+        prstatfs_to_statfs(response, &prstfs);
+        break;
+    }
+    case T_READLINK: {
+        V9fsString target;
+        v9fs_string_init(&target);
+        retval = proxy_unmarshal(reply, PROXY_HDR_SZ, "s", &target);
+        strcpy(response, target.data);
+        v9fs_string_free(&target);
+        break;
+    }
+    case T_LGETXATTR:
+    case T_LLISTXATTR: {
+        V9fsString xattr;
+        v9fs_string_init(&xattr);
+        retval = proxy_unmarshal(reply, PROXY_HDR_SZ, "s", &xattr);
+        memcpy(response, xattr.data, xattr.size);
+        v9fs_string_free(&xattr);
+        break;
+    }
+    case T_GETVERSION:
+        proxy_unmarshal(reply, PROXY_HDR_SZ, "q", response);
+        break;
+    default:
+        return -1;
+    }
+    if (retval < 0) {
+        *status  = retval;
+    }
+    return 0;
+}
+
+/*
+ * return < 0 on transport error.
+ * *status is valid only if return >= 0
+ */
+static int v9fs_receive_status(V9fsProxy *proxy,
+                               struct iovec *reply, int *status)
+{
+    int retval;
+    ProxyHeader header;
+
+    *status = 0;
+    reply->iov_len = 0;
+    retval = socket_read(proxy->sockfd, reply->iov_base, PROXY_HDR_SZ);
+    if (retval < 0) {
+        return retval;
+    }
+    reply->iov_len = PROXY_HDR_SZ;
+    proxy_unmarshal(reply, 0, "dd", &header.type, &header.size);
+    if (header.size != sizeof(int)) {
+        *status = -ENOBUFS;
+        return 0;
+    }
+    retval = socket_read(proxy->sockfd,
+                         reply->iov_base + PROXY_HDR_SZ, header.size);
+    if (retval < 0) {
+        return retval;
+    }
+    reply->iov_len += header.size;
+    proxy_unmarshal(reply, PROXY_HDR_SZ, "d", status);
+    return 0;
+}
+
+/*
+ * Proxy->header and proxy->request written to socket by QEMU process.
+ * This request read by proxy helper process
+ * returns 0 on success and -errno on error
+ */
+static int v9fs_request(V9fsProxy *proxy, int type,
+                        void *response, const char *fmt, ...)
+{
+    dev_t rdev;
+    va_list ap;
+    int size = 0;
+    int retval = 0;
+    uint64_t offset;
+    ProxyHeader header = { 0, 0};
+    struct timespec spec[2];
+    int flags, mode, uid, gid;
+    V9fsString *name, *value;
+    V9fsString *path, *oldpath;
+    struct iovec *iovec = NULL, *reply = NULL;
+
+    qemu_mutex_lock(&proxy->mutex);
+
+    if (proxy->sockfd == -1) {
+        retval = -EIO;
+        goto err_out;
+    }
+    iovec = &proxy->out_iovec;
+    reply = &proxy->in_iovec;
+    va_start(ap, fmt);
+    switch (type) {
+    case T_OPEN:
+        path = va_arg(ap, V9fsString *);
+        flags = va_arg(ap, int);
+        retval = proxy_marshal(iovec, PROXY_HDR_SZ, "sd", path, flags);
+        if (retval > 0) {
+            header.size = retval;
+            header.type = T_OPEN;
+        }
+        break;
+    case T_CREATE:
+        path = va_arg(ap, V9fsString *);
+        flags = va_arg(ap, int);
+        mode = va_arg(ap, int);
+        uid = va_arg(ap, int);
+        gid = va_arg(ap, int);
+        retval = proxy_marshal(iovec, PROXY_HDR_SZ, "sdddd", path,
+                                    flags, mode, uid, gid);
+        if (retval > 0) {
+            header.size = retval;
+            header.type = T_CREATE;
+        }
+        break;
+    case T_MKNOD:
+        path = va_arg(ap, V9fsString *);
+        mode = va_arg(ap, int);
+        rdev = va_arg(ap, long int);
+        uid = va_arg(ap, int);
+        gid = va_arg(ap, int);
+        retval = proxy_marshal(iovec, PROXY_HDR_SZ, "ddsdq",
+                                    uid, gid, path, mode, rdev);
+        if (retval > 0) {
+            header.size = retval;
+            header.type = T_MKNOD;
+        }
+        break;
+    case T_MKDIR:
+        path = va_arg(ap, V9fsString *);
+        mode = va_arg(ap, int);
+        uid = va_arg(ap, int);
+        gid = va_arg(ap, int);
+        retval = proxy_marshal(iovec, PROXY_HDR_SZ, "ddsd",
+                                    uid, gid, path, mode);
+        if (retval > 0) {
+            header.size = retval;
+            header.type = T_MKDIR;
+        }
+        break;
+    case T_SYMLINK:
+        oldpath = va_arg(ap, V9fsString *);
+        path = va_arg(ap, V9fsString *);
+        uid = va_arg(ap, int);
+        gid = va_arg(ap, int);
+        retval = proxy_marshal(iovec, PROXY_HDR_SZ, "ddss",
+                                    uid, gid, oldpath, path);
+        if (retval > 0) {
+            header.size = retval;
+            header.type = T_SYMLINK;
+        }
+        break;
+    case T_LINK:
+        oldpath = va_arg(ap, V9fsString *);
+        path = va_arg(ap, V9fsString *);
+        retval = proxy_marshal(iovec, PROXY_HDR_SZ, "ss",
+                                    oldpath, path);
+        if (retval > 0) {
+            header.size = retval;
+            header.type = T_LINK;
+        }
+        break;
+    case T_LSTAT:
+        path = va_arg(ap, V9fsString *);
+        retval = proxy_marshal(iovec, PROXY_HDR_SZ, "s", path);
+        if (retval > 0) {
+            header.size = retval;
+            header.type = T_LSTAT;
+        }
+        break;
+    case T_READLINK:
+        path = va_arg(ap, V9fsString *);
+        size = va_arg(ap, int);
+        retval = proxy_marshal(iovec, PROXY_HDR_SZ, "sd", path, size);
+        if (retval > 0) {
+            header.size = retval;
+            header.type = T_READLINK;
+        }
+        break;
+    case T_STATFS:
+        path = va_arg(ap, V9fsString *);
+        retval = proxy_marshal(iovec, PROXY_HDR_SZ, "s", path);
+        if (retval > 0) {
+            header.size = retval;
+            header.type = T_STATFS;
+        }
+        break;
+    case T_CHMOD:
+        path = va_arg(ap, V9fsString *);
+        mode = va_arg(ap, int);
+        retval = proxy_marshal(iovec, PROXY_HDR_SZ, "sd", path, mode);
+        if (retval > 0) {
+            header.size = retval;
+            header.type = T_CHMOD;
+        }
+        break;
+    case T_CHOWN:
+        path = va_arg(ap, V9fsString *);
+        uid = va_arg(ap, int);
+        gid = va_arg(ap, int);
+        retval = proxy_marshal(iovec, PROXY_HDR_SZ, "sdd", path, uid, gid);
+        if (retval > 0) {
+            header.size = retval;
+            header.type = T_CHOWN;
+        }
+        break;
+    case T_TRUNCATE:
+        path = va_arg(ap, V9fsString *);
+        offset = va_arg(ap, uint64_t);
+        retval = proxy_marshal(iovec, PROXY_HDR_SZ, "sq", path, offset);
+        if (retval > 0) {
+            header.size = retval;
+            header.type = T_TRUNCATE;
+        }
+        break;
+    case T_UTIME:
+        path = va_arg(ap, V9fsString *);
+        spec[0].tv_sec = va_arg(ap, long);
+        spec[0].tv_nsec = va_arg(ap, long);
+        spec[1].tv_sec = va_arg(ap, long);
+        spec[1].tv_nsec = va_arg(ap, long);
+        retval = proxy_marshal(iovec, PROXY_HDR_SZ, "sqqqq", path,
+                                    spec[0].tv_sec, spec[1].tv_nsec,
+                                    spec[1].tv_sec, spec[1].tv_nsec);
+        if (retval > 0) {
+            header.size = retval;
+            header.type = T_UTIME;
+        }
+        break;
+    case T_RENAME:
+        oldpath = va_arg(ap, V9fsString *);
+        path = va_arg(ap, V9fsString *);
+        retval = proxy_marshal(iovec, PROXY_HDR_SZ, "ss", oldpath, path);
+        if (retval > 0) {
+            header.size = retval;
+            header.type = T_RENAME;
+        }
+        break;
+    case T_REMOVE:
+        path = va_arg(ap, V9fsString *);
+        retval = proxy_marshal(iovec, PROXY_HDR_SZ, "s", path);
+        if (retval > 0) {
+            header.size = retval;
+            header.type = T_REMOVE;
+        }
+        break;
+    case T_LGETXATTR:
+        size = va_arg(ap, int);
+        path = va_arg(ap, V9fsString *);
+        name = va_arg(ap, V9fsString *);
+        retval = proxy_marshal(iovec, PROXY_HDR_SZ,
+                                    "dss", size, path, name);
+        if (retval > 0) {
+            header.size = retval;
+            header.type = T_LGETXATTR;
+        }
+        break;
+    case T_LLISTXATTR:
+        size = va_arg(ap, int);
+        path = va_arg(ap, V9fsString *);
+        retval = proxy_marshal(iovec, PROXY_HDR_SZ, "ds", size, path);
+        if (retval > 0) {
+            header.size = retval;
+            header.type = T_LLISTXATTR;
+        }
+        break;
+    case T_LSETXATTR:
+        path = va_arg(ap, V9fsString *);
+        name = va_arg(ap, V9fsString *);
+        value = va_arg(ap, V9fsString *);
+        size = va_arg(ap, int);
+        flags = va_arg(ap, int);
+        retval = proxy_marshal(iovec, PROXY_HDR_SZ, "sssdd",
+                                    path, name, value, size, flags);
+        if (retval > 0) {
+            header.size = retval;
+            header.type = T_LSETXATTR;
+        }
+        break;
+    case T_LREMOVEXATTR:
+        path = va_arg(ap, V9fsString *);
+        name = va_arg(ap, V9fsString *);
+        retval = proxy_marshal(iovec, PROXY_HDR_SZ, "ss", path, name);
+        if (retval > 0) {
+            header.size = retval;
+            header.type = T_LREMOVEXATTR;
+        }
+        break;
+    case T_GETVERSION:
+        path = va_arg(ap, V9fsString *);
+        retval = proxy_marshal(iovec, PROXY_HDR_SZ, "s", path);
+        if (retval > 0) {
+            header.size = retval;
+            header.type = T_GETVERSION;
+        }
+        break;
+    default:
+        error_report("Invalid type %d\n", type);
+        retval = -EINVAL;
+        break;
+    }
+    va_end(ap);
+
+    if (retval < 0) {
+        goto err_out;
+    }
+
+    /* marshal the header details */
+    proxy_marshal(iovec, 0, "dd", header.type, header.size);
+    header.size += PROXY_HDR_SZ;
+
+    retval = qemu_write_full(proxy->sockfd, iovec->iov_base, header.size);
+    if (retval != header.size) {
+        goto close_error;
+    }
+
+    switch (type) {
+    case T_OPEN:
+    case T_CREATE:
+        /*
+         * A file descriptor is returned as response for
+         * T_OPEN,T_CREATE on success
+         */
+        if (v9fs_receivefd(proxy->sockfd, &retval) < 0) {
+            goto close_error;
+        }
+        break;
+    case T_MKNOD:
+    case T_MKDIR:
+    case T_SYMLINK:
+    case T_LINK:
+    case T_CHMOD:
+    case T_CHOWN:
+    case T_RENAME:
+    case T_TRUNCATE:
+    case T_UTIME:
+    case T_REMOVE:
+    case T_LSETXATTR:
+    case T_LREMOVEXATTR:
+        if (v9fs_receive_status(proxy, reply, &retval) < 0) {
+            goto close_error;
+        }
+        break;
+    case T_LSTAT:
+    case T_READLINK:
+    case T_STATFS:
+    case T_GETVERSION:
+        if (v9fs_receive_response(proxy, type, &retval, response) < 0) {
+            goto close_error;
+        }
+        break;
+    case T_LGETXATTR:
+    case T_LLISTXATTR:
+        if (!size) {
+            if (v9fs_receive_status(proxy, reply, &retval) < 0) {
+                goto close_error;
+            }
+        } else {
+            if (v9fs_receive_response(proxy, type, &retval, response) < 0) {
+                goto close_error;
+            }
+        }
+        break;
+    }
+
+err_out:
+    qemu_mutex_unlock(&proxy->mutex);
+    return retval;
+
+close_error:
+    close(proxy->sockfd);
+    proxy->sockfd = -1;
+    qemu_mutex_unlock(&proxy->mutex);
+    return -EIO;
+}
+
+static int proxy_lstat(FsContext *fs_ctx, V9fsPath *fs_path, struct stat *stbuf)
+{
+    int retval;
+    retval = v9fs_request(fs_ctx->private, T_LSTAT, stbuf, "s", fs_path);
+    if (retval < 0) {
+        errno = -retval;
+        return -1;
+    }
+    return retval;
+}
+
+static ssize_t proxy_readlink(FsContext *fs_ctx, V9fsPath *fs_path,
+                              char *buf, size_t bufsz)
+{
+    int retval;
+    retval = v9fs_request(fs_ctx->private, T_READLINK, buf, "sd",
+                          fs_path, bufsz);
+    if (retval < 0) {
+        errno = -retval;
+        return -1;
+    }
+    return strlen(buf);
+}
+
+static int proxy_close(FsContext *ctx, V9fsFidOpenState *fs)
+{
+    return close(fs->fd);
+}
+
+static int proxy_closedir(FsContext *ctx, V9fsFidOpenState *fs)
+{
+    return closedir(fs->dir);
+}
+
+static int proxy_open(FsContext *ctx, V9fsPath *fs_path,
+                      int flags, V9fsFidOpenState *fs)
+{
+    fs->fd = v9fs_request(ctx->private, T_OPEN, NULL, "sd", fs_path, flags);
+    if (fs->fd < 0) {
+        errno = -fs->fd;
+        fs->fd = -1;
+    }
+    return fs->fd;
+}
+
+static int proxy_opendir(FsContext *ctx,
+                         V9fsPath *fs_path, V9fsFidOpenState *fs)
+{
+    int serrno, fd;
+
+    fs->dir = NULL;
+    fd = v9fs_request(ctx->private, T_OPEN, NULL, "sd", fs_path, O_DIRECTORY);
+    if (fd < 0) {
+        errno = -fd;
+        return -1;
+    }
+    fs->dir = fdopendir(fd);
+    if (!fs->dir) {
+        serrno = errno;
+        close(fd);
+        errno = serrno;
+        return -1;
+    }
+    return 0;
+}
+
+static void proxy_rewinddir(FsContext *ctx, V9fsFidOpenState *fs)
+{
+    return rewinddir(fs->dir);
+}
+
+static off_t proxy_telldir(FsContext *ctx, V9fsFidOpenState *fs)
+{
+    return telldir(fs->dir);
+}
+
+static int proxy_readdir_r(FsContext *ctx, V9fsFidOpenState *fs,
+                           struct dirent *entry,
+                           struct dirent **result)
+{
+    return readdir_r(fs->dir, entry, result);
+}
+
+static void proxy_seekdir(FsContext *ctx, V9fsFidOpenState *fs, off_t off)
+{
+    return seekdir(fs->dir, off);
+}
+
+static ssize_t proxy_preadv(FsContext *ctx, V9fsFidOpenState *fs,
+                            const struct iovec *iov,
+                            int iovcnt, off_t offset)
+{
+#ifdef CONFIG_PREADV
+    return preadv(fs->fd, iov, iovcnt, offset);
+#else
+    int err = lseek(fs->fd, offset, SEEK_SET);
+    if (err == -1) {
+        return err;
+    } else {
+        return readv(fs->fd, iov, iovcnt);
+    }
+#endif
+}
+
+static ssize_t proxy_pwritev(FsContext *ctx, V9fsFidOpenState *fs,
+                             const struct iovec *iov,
+                             int iovcnt, off_t offset)
+{
+    ssize_t ret;
+
+#ifdef CONFIG_PREADV
+    ret = pwritev(fs->fd, iov, iovcnt, offset);
+#else
+    int err = lseek(fs->fd, offset, SEEK_SET);
+    if (err == -1) {
+        return err;
+    } else {
+        ret = writev(fs->fd, iov, iovcnt);
+    }
+#endif
+#ifdef CONFIG_SYNC_FILE_RANGE
+    if (ret > 0 && ctx->export_flags & V9FS_IMMEDIATE_WRITEOUT) {
+        /*
+         * Initiate a writeback. This is not a data integrity sync.
+         * We want to ensure that we don't leave dirty pages in the cache
+         * after write when writeout=immediate is sepcified.
+         */
+        sync_file_range(fs->fd, offset, ret,
+                        SYNC_FILE_RANGE_WAIT_BEFORE | SYNC_FILE_RANGE_WRITE);
+    }
+#endif
+    return ret;
+}
+
+static int proxy_chmod(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp)
+{
+    int retval;
+    retval = v9fs_request(fs_ctx->private, T_CHMOD, NULL, "sd",
+                          fs_path, credp->fc_mode);
+    if (retval < 0) {
+        errno = -retval;
+    }
+    return retval;
+}
+
+static int proxy_mknod(FsContext *fs_ctx, V9fsPath *dir_path,
+                       const char *name, FsCred *credp)
+{
+    int retval;
+    V9fsString fullname;
+
+    v9fs_string_init(&fullname);
+    v9fs_string_sprintf(&fullname, "%s/%s", dir_path->data, name);
+
+    retval = v9fs_request(fs_ctx->private, T_MKNOD, NULL, "sdqdd",
+                          &fullname, credp->fc_mode, credp->fc_rdev,
+                          credp->fc_uid, credp->fc_gid);
+    v9fs_string_free(&fullname);
+    if (retval < 0) {
+        errno = -retval;
+        retval = -1;
+    }
+    return retval;
+}
+
+static int proxy_mkdir(FsContext *fs_ctx, V9fsPath *dir_path,
+                       const char *name, FsCred *credp)
+{
+    int retval;
+    V9fsString fullname;
+
+    v9fs_string_init(&fullname);
+    v9fs_string_sprintf(&fullname, "%s/%s", dir_path->data, name);
+
+    retval = v9fs_request(fs_ctx->private, T_MKDIR, NULL, "sddd", &fullname,
+                          credp->fc_mode, credp->fc_uid, credp->fc_gid);
+    v9fs_string_free(&fullname);
+    if (retval < 0) {
+        errno = -retval;
+        retval = -1;
+    }
+    v9fs_string_free(&fullname);
+    return retval;
+}
+
+static int proxy_fstat(FsContext *fs_ctx, int fid_type,
+                       V9fsFidOpenState *fs, struct stat *stbuf)
+{
+    int fd;
+
+    if (fid_type == P9_FID_DIR) {
+        fd = dirfd(fs->dir);
+    } else {
+        fd = fs->fd;
+    }
+    return fstat(fd, stbuf);
+}
+
+static int proxy_open2(FsContext *fs_ctx, V9fsPath *dir_path, const char *name,
+                       int flags, FsCred *credp, V9fsFidOpenState *fs)
+{
+    V9fsString fullname;
+
+    v9fs_string_init(&fullname);
+    v9fs_string_sprintf(&fullname, "%s/%s", dir_path->data, name);
+
+    fs->fd = v9fs_request(fs_ctx->private, T_CREATE, NULL, "sdddd",
+                          &fullname, flags, credp->fc_mode,
+                          credp->fc_uid, credp->fc_gid);
+    v9fs_string_free(&fullname);
+    if (fs->fd < 0) {
+        errno = -fs->fd;
+        fs->fd = -1;
+    }
+    return fs->fd;
+}
+
+static int proxy_symlink(FsContext *fs_ctx, const char *oldpath,
+                         V9fsPath *dir_path, const char *name, FsCred *credp)
+{
+    int retval;
+    V9fsString fullname, target;
+
+    v9fs_string_init(&fullname);
+    v9fs_string_init(&target);
+
+    v9fs_string_sprintf(&fullname, "%s/%s", dir_path->data, name);
+    v9fs_string_sprintf(&target, "%s", oldpath);
+
+    retval = v9fs_request(fs_ctx->private, T_SYMLINK, NULL, "ssdd",
+                          &target, &fullname, credp->fc_uid, credp->fc_gid);
+    v9fs_string_free(&fullname);
+    v9fs_string_free(&target);
+    if (retval < 0) {
+        errno = -retval;
+        retval = -1;
+    }
+    return retval;
+}
+
+static int proxy_link(FsContext *ctx, V9fsPath *oldpath,
+                      V9fsPath *dirpath, const char *name)
+{
+    int retval;
+    V9fsString newpath;
+
+    v9fs_string_init(&newpath);
+    v9fs_string_sprintf(&newpath, "%s/%s", dirpath->data, name);
+
+    retval = v9fs_request(ctx->private, T_LINK, NULL, "ss", oldpath, &newpath);
+    v9fs_string_free(&newpath);
+    if (retval < 0) {
+        errno = -retval;
+        retval = -1;
+    }
+    return retval;
+}
+
+static int proxy_truncate(FsContext *ctx, V9fsPath *fs_path, off_t size)
+{
+    int retval;
+
+    retval = v9fs_request(ctx->private, T_TRUNCATE, NULL, "sq", fs_path, size);
+    if (retval < 0) {
+        errno = -retval;
+        return -1;
+    }
+    return 0;
+}
+
+static int proxy_rename(FsContext *ctx, const char *oldpath,
+                        const char *newpath)
+{
+    int retval;
+    V9fsString oldname, newname;
+
+    v9fs_string_init(&oldname);
+    v9fs_string_init(&newname);
+
+    v9fs_string_sprintf(&oldname, "%s", oldpath);
+    v9fs_string_sprintf(&newname, "%s", newpath);
+    retval = v9fs_request(ctx->private, T_RENAME, NULL, "ss",
+                          &oldname, &newname);
+    v9fs_string_free(&oldname);
+    v9fs_string_free(&newname);
+    if (retval < 0) {
+        errno = -retval;
+    }
+    return retval;
+}
+
+static int proxy_chown(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp)
+{
+    int retval;
+    retval = v9fs_request(fs_ctx->private, T_CHOWN, NULL, "sdd",
+                          fs_path, credp->fc_uid, credp->fc_gid);
+    if (retval < 0) {
+        errno = -retval;
+    }
+    return retval;
+}
+
+static int proxy_utimensat(FsContext *s, V9fsPath *fs_path,
+                           const struct timespec *buf)
+{
+    int retval;
+    retval = v9fs_request(s->private, T_UTIME, NULL, "sqqqq",
+                          fs_path,
+                          buf[0].tv_sec, buf[0].tv_nsec,
+                          buf[1].tv_sec, buf[1].tv_nsec);
+    if (retval < 0) {
+        errno = -retval;
+    }
+    return retval;
+}
+
+static int proxy_remove(FsContext *ctx, const char *path)
+{
+    int retval;
+    V9fsString name;
+    v9fs_string_init(&name);
+    v9fs_string_sprintf(&name, "%s", path);
+    retval = v9fs_request(ctx->private, T_REMOVE, NULL, "s", &name);
+    v9fs_string_free(&name);
+    if (retval < 0) {
+        errno = -retval;
+    }
+    return retval;
+}
+
+static int proxy_fsync(FsContext *ctx, int fid_type,
+                       V9fsFidOpenState *fs, int datasync)
+{
+    int fd;
+
+    if (fid_type == P9_FID_DIR) {
+        fd = dirfd(fs->dir);
+    } else {
+        fd = fs->fd;
+    }
+
+    if (datasync) {
+        return qemu_fdatasync(fd);
+    } else {
+        return fsync(fd);
+    }
+}
+
+static int proxy_statfs(FsContext *s, V9fsPath *fs_path, struct statfs *stbuf)
+{
+    int retval;
+    retval = v9fs_request(s->private, T_STATFS, stbuf, "s", fs_path);
+    if (retval < 0) {
+        errno = -retval;
+        return -1;
+    }
+    return retval;
+}
+
+static ssize_t proxy_lgetxattr(FsContext *ctx, V9fsPath *fs_path,
+                               const char *name, void *value, size_t size)
+{
+    int retval;
+    V9fsString xname;
+
+    v9fs_string_init(&xname);
+    v9fs_string_sprintf(&xname, "%s", name);
+    retval = v9fs_request(ctx->private, T_LGETXATTR, value, "dss", size,
+                          fs_path, &xname);
+    v9fs_string_free(&xname);
+    if (retval < 0) {
+        errno = -retval;
+    }
+    return retval;
+}
+
+static ssize_t proxy_llistxattr(FsContext *ctx, V9fsPath *fs_path,
+                                void *value, size_t size)
+{
+    int retval;
+    retval = v9fs_request(ctx->private, T_LLISTXATTR, value, "ds", size,
+                        fs_path);
+    if (retval < 0) {
+        errno = -retval;
+    }
+    return retval;
+}
+
+static int proxy_lsetxattr(FsContext *ctx, V9fsPath *fs_path, const char *name,
+                           void *value, size_t size, int flags)
+{
+    int retval;
+    V9fsString xname, xvalue;
+
+    v9fs_string_init(&xname);
+    v9fs_string_sprintf(&xname, "%s", name);
+
+    v9fs_string_init(&xvalue);
+    xvalue.size = size;
+    xvalue.data = g_malloc(size);
+    memcpy(xvalue.data, value, size);
+
+    retval = v9fs_request(ctx->private, T_LSETXATTR, value, "sssdd",
+                          fs_path, &xname, &xvalue, size, flags);
+    v9fs_string_free(&xname);
+    v9fs_string_free(&xvalue);
+    if (retval < 0) {
+        errno = -retval;
+    }
+    return retval;
+}
+
+static int proxy_lremovexattr(FsContext *ctx, V9fsPath *fs_path,
+                              const char *name)
+{
+    int retval;
+    V9fsString xname;
+
+    v9fs_string_init(&xname);
+    v9fs_string_sprintf(&xname, "%s", name);
+    retval = v9fs_request(ctx->private, T_LREMOVEXATTR, NULL, "ss",
+                          fs_path, &xname);
+    v9fs_string_free(&xname);
+    if (retval < 0) {
+        errno = -retval;
+    }
+    return retval;
+}
+
+static int proxy_name_to_path(FsContext *ctx, V9fsPath *dir_path,
+                              const char *name, V9fsPath *target)
+{
+    if (dir_path) {
+        v9fs_string_sprintf((V9fsString *)target, "%s/%s",
+                            dir_path->data, name);
+    } else {
+        v9fs_string_sprintf((V9fsString *)target, "%s", name);
+    }
+    /* Bump the size for including terminating NULL */
+    target->size++;
+    return 0;
+}
+
+static int proxy_renameat(FsContext *ctx, V9fsPath *olddir,
+                          const char *old_name, V9fsPath *newdir,
+                          const char *new_name)
+{
+    int ret;
+    V9fsString old_full_name, new_full_name;
+
+    v9fs_string_init(&old_full_name);
+    v9fs_string_init(&new_full_name);
+
+    v9fs_string_sprintf(&old_full_name, "%s/%s", olddir->data, old_name);
+    v9fs_string_sprintf(&new_full_name, "%s/%s", newdir->data, new_name);
+
+    ret = proxy_rename(ctx, old_full_name.data, new_full_name.data);
+    v9fs_string_free(&old_full_name);
+    v9fs_string_free(&new_full_name);
+    return ret;
+}
+
+static int proxy_unlinkat(FsContext *ctx, V9fsPath *dir,
+                          const char *name, int flags)
+{
+    int ret;
+    V9fsString fullname;
+    v9fs_string_init(&fullname);
+
+    v9fs_string_sprintf(&fullname, "%s/%s", dir->data, name);
+    ret = proxy_remove(ctx, fullname.data);
+    v9fs_string_free(&fullname);
+
+    return ret;
+}
+
+static int proxy_ioc_getversion(FsContext *fs_ctx, V9fsPath *path,
+                                mode_t st_mode, uint64_t *st_gen)
+{
+    int err;
+
+    /* Do not try to open special files like device nodes, fifos etc
+     * we can get fd for regular files and directories only
+     */
+    if (!S_ISREG(st_mode) && !S_ISDIR(st_mode)) {
+        return 0;
+    }
+    err = v9fs_request(fs_ctx->private, T_GETVERSION, st_gen, "s", path);
+    if (err < 0) {
+        errno = -err;
+        err = -1;
+    }
+    return err;
+}
+
+static int connect_namedsocket(const char *path)
+{
+    int sockfd, size;
+    struct sockaddr_un helper;
+
+    sockfd = socket(AF_UNIX, SOCK_STREAM, 0);
+    if (sockfd < 0) {
+        fprintf(stderr, "socket %s\n", strerror(errno));
+        return -1;
+    }
+    strcpy(helper.sun_path, path);
+    helper.sun_family = AF_UNIX;
+    size = strlen(helper.sun_path) + sizeof(helper.sun_family);
+    if (connect(sockfd, (struct sockaddr *)&helper, size) < 0) {
+        fprintf(stderr, "socket error\n");
+        return -1;
+    }
+
+    /* remove the socket for security reasons */
+    unlink(path);
+    return sockfd;
+}
+
+static int proxy_parse_opts(QemuOpts *opts, struct FsDriverEntry *fs)
+{
+    const char *socket = qemu_opt_get(opts, "socket");
+    const char *sock_fd = qemu_opt_get(opts, "sock_fd");
+
+    if (!socket && !sock_fd) {
+        fprintf(stderr, "socket and sock_fd none of the option specified\n");
+        return -1;
+    }
+    if (socket && sock_fd) {
+        fprintf(stderr, "Both socket and sock_fd options specified\n");
+        return -1;
+    }
+    if (socket) {
+        fs->path = g_strdup(socket);
+        fs->export_flags = V9FS_PROXY_SOCK_NAME;
+    } else {
+        fs->path = g_strdup(sock_fd);
+        fs->export_flags = V9FS_PROXY_SOCK_FD;
+    }
+    return 0;
+}
+
+static int proxy_init(FsContext *ctx)
+{
+    V9fsProxy *proxy = g_malloc(sizeof(V9fsProxy));
+    int sock_id;
+
+    if (ctx->export_flags & V9FS_PROXY_SOCK_NAME) {
+        sock_id = connect_namedsocket(ctx->fs_root);
+    } else {
+        sock_id = atoi(ctx->fs_root);
+        if (sock_id < 0) {
+            fprintf(stderr, "socket descriptor not initialized\n");
+            return -1;
+        }
+    }
+    g_free(ctx->fs_root);
+
+    proxy->in_iovec.iov_base  = g_malloc(PROXY_MAX_IO_SZ + PROXY_HDR_SZ);
+    proxy->in_iovec.iov_len   = PROXY_MAX_IO_SZ + PROXY_HDR_SZ;
+    proxy->out_iovec.iov_base = g_malloc(PROXY_MAX_IO_SZ + PROXY_HDR_SZ);
+    proxy->out_iovec.iov_len  = PROXY_MAX_IO_SZ + PROXY_HDR_SZ;
+
+    ctx->private = proxy;
+    proxy->sockfd = sock_id;
+    qemu_mutex_init(&proxy->mutex);
+
+    ctx->export_flags |= V9FS_PATHNAME_FSCONTEXT;
+    ctx->exops.get_st_gen = proxy_ioc_getversion;
+    return 0;
+}
+
+FileOperations proxy_ops = {
+    .parse_opts   = proxy_parse_opts,
+    .init         = proxy_init,
+    .lstat        = proxy_lstat,
+    .readlink     = proxy_readlink,
+    .close        = proxy_close,
+    .closedir     = proxy_closedir,
+    .open         = proxy_open,
+    .opendir      = proxy_opendir,
+    .rewinddir    = proxy_rewinddir,
+    .telldir      = proxy_telldir,
+    .readdir_r    = proxy_readdir_r,
+    .seekdir      = proxy_seekdir,
+    .preadv       = proxy_preadv,
+    .pwritev      = proxy_pwritev,
+    .chmod        = proxy_chmod,
+    .mknod        = proxy_mknod,
+    .mkdir        = proxy_mkdir,
+    .fstat        = proxy_fstat,
+    .open2        = proxy_open2,
+    .symlink      = proxy_symlink,
+    .link         = proxy_link,
+    .truncate     = proxy_truncate,
+    .rename       = proxy_rename,
+    .chown        = proxy_chown,
+    .utimensat    = proxy_utimensat,
+    .remove       = proxy_remove,
+    .fsync        = proxy_fsync,
+    .statfs       = proxy_statfs,
+    .lgetxattr    = proxy_lgetxattr,
+    .llistxattr   = proxy_llistxattr,
+    .lsetxattr    = proxy_lsetxattr,
+    .lremovexattr = proxy_lremovexattr,
+    .name_to_path = proxy_name_to_path,
+    .renameat     = proxy_renameat,
+    .unlinkat     = proxy_unlinkat,
+};
diff --git a/hw/9pfs/virtio-9p-proxy.h b/hw/9pfs/virtio-9p-proxy.h
new file mode 100644
index 0000000000..005c1ad757
--- /dev/null
+++ b/hw/9pfs/virtio-9p-proxy.h
@@ -0,0 +1,95 @@
+/*
+ * Virtio 9p Proxy callback
+ *
+ * Copyright IBM, Corp. 2011
+ *
+ * Authors:
+ * M. Mohan Kumar <mohan@in.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ */
+#ifndef _QEMU_VIRTIO_9P_PROXY_H
+#define _QEMU_VIRTIO_9P_PROXY_H
+
+#define PROXY_MAX_IO_SZ (64 * 1024)
+#define V9FS_FD_VALID INT_MAX
+
+/*
+ * proxy iovec only support one element and
+ * marsha/unmarshal doesn't do little endian conversion.
+ */
+#define proxy_unmarshal(in_sg, offset, fmt, args...) \
+    v9fs_unmarshal(in_sg, 1, offset, 0, fmt, ##args)
+#define proxy_marshal(out_sg, offset, fmt, args...) \
+    v9fs_marshal(out_sg, 1, offset, 0, fmt, ##args)
+
+union MsgControl {
+    struct cmsghdr cmsg;
+    char control[CMSG_SPACE(sizeof(int))];
+};
+
+typedef struct {
+    uint32_t type;
+    uint32_t size;
+} ProxyHeader;
+
+#define PROXY_HDR_SZ (sizeof(ProxyHeader))
+
+enum {
+    T_SUCCESS = 0,
+    T_ERROR,
+    T_OPEN,
+    T_CREATE,
+    T_MKNOD,
+    T_MKDIR,
+    T_SYMLINK,
+    T_LINK,
+    T_LSTAT,
+    T_READLINK,
+    T_STATFS,
+    T_CHMOD,
+    T_CHOWN,
+    T_TRUNCATE,
+    T_UTIME,
+    T_RENAME,
+    T_REMOVE,
+    T_LGETXATTR,
+    T_LLISTXATTR,
+    T_LSETXATTR,
+    T_LREMOVEXATTR,
+    T_GETVERSION,
+};
+
+typedef struct {
+    uint64_t st_dev;
+    uint64_t st_ino;
+    uint64_t st_nlink;
+    uint32_t st_mode;
+    uint32_t st_uid;
+    uint32_t st_gid;
+    uint64_t st_rdev;
+    uint64_t st_size;
+    uint64_t st_blksize;
+    uint64_t st_blocks;
+    uint64_t st_atim_sec;
+    uint64_t st_atim_nsec;
+    uint64_t st_mtim_sec;
+    uint64_t st_mtim_nsec;
+    uint64_t st_ctim_sec;
+    uint64_t st_ctim_nsec;
+} ProxyStat;
+
+typedef struct {
+    uint64_t f_type;
+    uint64_t f_bsize;
+    uint64_t f_blocks;
+    uint64_t f_bfree;
+    uint64_t f_bavail;
+    uint64_t f_files;
+    uint64_t f_ffree;
+    uint64_t f_fsid[2];
+    uint64_t f_namelen;
+    uint64_t f_frsize;
+} ProxyStatFS;
+#endif
diff --git a/hw/9pfs/virtio-9p.c b/hw/9pfs/virtio-9p.c
index df0a8e731b..e6ba6ba30b 100644
--- a/hw/9pfs/virtio-9p.c
+++ b/hw/9pfs/virtio-9p.c
@@ -11,9 +11,6 @@
  *
  */
 
-#include <glib.h>
-#include <glib/gprintf.h>
-
 #include "hw/virtio.h"
 #include "hw/pc.h"
 #include "qemu_socket.h"
@@ -138,42 +135,6 @@ static int get_dotl_openflags(V9fsState *s, int oflags)
     return flags;
 }
 
-void v9fs_string_init(V9fsString *str)
-{
-    str->data = NULL;
-    str->size = 0;
-}
-
-void v9fs_string_free(V9fsString *str)
-{
-    g_free(str->data);
-    str->data = NULL;
-    str->size = 0;
-}
-
-void v9fs_string_null(V9fsString *str)
-{
-    v9fs_string_free(str);
-}
-
-void GCC_FMT_ATTR(2, 3)
-v9fs_string_sprintf(V9fsString *str, const char *fmt, ...)
-{
-    va_list ap;
-
-    v9fs_string_free(str);
-
-    va_start(ap, fmt);
-    str->size = g_vasprintf(&str->data, fmt, ap);
-    va_end(ap);
-}
-
-void v9fs_string_copy(V9fsString *lhs, V9fsString *rhs)
-{
-    v9fs_string_free(lhs);
-    v9fs_string_sprintf(lhs, "%s", rhs->data);
-}
-
 void v9fs_path_init(V9fsPath *path)
 {
     path->data = NULL;
@@ -629,211 +590,11 @@ static void free_pdu(V9fsState *s, V9fsPDU *pdu)
     }
 }
 
-size_t pdu_packunpack(void *addr, struct iovec *sg, int sg_count,
-                        size_t offset, size_t size, int pack)
-{
-    int i = 0;
-    size_t copied = 0;
-
-    for (i = 0; size && i < sg_count; i++) {
-        size_t len;
-        if (offset >= sg[i].iov_len) {
-            /* skip this sg */
-            offset -= sg[i].iov_len;
-            continue;
-        } else {
-            len = MIN(sg[i].iov_len - offset, size);
-            if (pack) {
-                memcpy(sg[i].iov_base + offset, addr, len);
-            } else {
-                memcpy(addr, sg[i].iov_base + offset, len);
-            }
-            size -= len;
-            copied += len;
-            addr += len;
-            if (size) {
-                offset = 0;
-                continue;
-            }
-        }
-    }
-
-    return copied;
-}
-
-static size_t pdu_unpack(void *dst, V9fsPDU *pdu, size_t offset, size_t size)
-{
-    return pdu_packunpack(dst, pdu->elem.out_sg, pdu->elem.out_num,
-                         offset, size, 0);
-}
-
-static size_t pdu_pack(V9fsPDU *pdu, size_t offset, const void *src,
-                        size_t size)
-{
-    return pdu_packunpack((void *)src, pdu->elem.in_sg, pdu->elem.in_num,
-                             offset, size, 1);
-}
-
-static size_t pdu_unmarshal(V9fsPDU *pdu, size_t offset, const char *fmt, ...)
-{
-    size_t old_offset = offset;
-    va_list ap;
-    int i;
-
-    va_start(ap, fmt);
-    for (i = 0; fmt[i]; i++) {
-        switch (fmt[i]) {
-        case 'b': {
-            uint8_t *valp = va_arg(ap, uint8_t *);
-            offset += pdu_unpack(valp, pdu, offset, sizeof(*valp));
-            break;
-        }
-        case 'w': {
-            uint16_t val, *valp;
-            valp = va_arg(ap, uint16_t *);
-            offset += pdu_unpack(&val, pdu, offset, sizeof(val));
-            *valp = le16_to_cpu(val);
-            break;
-        }
-        case 'd': {
-            uint32_t val, *valp;
-            valp = va_arg(ap, uint32_t *);
-            offset += pdu_unpack(&val, pdu, offset, sizeof(val));
-            *valp = le32_to_cpu(val);
-            break;
-        }
-        case 'q': {
-            uint64_t val, *valp;
-            valp = va_arg(ap, uint64_t *);
-            offset += pdu_unpack(&val, pdu, offset, sizeof(val));
-            *valp = le64_to_cpu(val);
-            break;
-        }
-        case 's': {
-            V9fsString *str = va_arg(ap, V9fsString *);
-            offset += pdu_unmarshal(pdu, offset, "w", &str->size);
-            /* FIXME: sanity check str->size */
-            str->data = g_malloc(str->size + 1);
-            offset += pdu_unpack(str->data, pdu, offset, str->size);
-            str->data[str->size] = 0;
-            break;
-        }
-        case 'Q': {
-            V9fsQID *qidp = va_arg(ap, V9fsQID *);
-            offset += pdu_unmarshal(pdu, offset, "bdq",
-                        &qidp->type, &qidp->version, &qidp->path);
-            break;
-        }
-        case 'S': {
-            V9fsStat *statp = va_arg(ap, V9fsStat *);
-            offset += pdu_unmarshal(pdu, offset, "wwdQdddqsssssddd",
-                        &statp->size, &statp->type, &statp->dev,
-                        &statp->qid, &statp->mode, &statp->atime,
-                        &statp->mtime, &statp->length,
-                        &statp->name, &statp->uid, &statp->gid,
-                        &statp->muid, &statp->extension,
-                        &statp->n_uid, &statp->n_gid,
-                        &statp->n_muid);
-            break;
-        }
-        case 'I': {
-            V9fsIattr *iattr = va_arg(ap, V9fsIattr *);
-            offset += pdu_unmarshal(pdu, offset, "ddddqqqqq",
-                        &iattr->valid, &iattr->mode,
-                        &iattr->uid, &iattr->gid, &iattr->size,
-                        &iattr->atime_sec, &iattr->atime_nsec,
-                        &iattr->mtime_sec, &iattr->mtime_nsec);
-            break;
-        }
-        default:
-            break;
-        }
-    }
-
-    va_end(ap);
-
-    return offset - old_offset;
-}
-
-static size_t pdu_marshal(V9fsPDU *pdu, size_t offset, const char *fmt, ...)
-{
-    size_t old_offset = offset;
-    va_list ap;
-    int i;
-
-    va_start(ap, fmt);
-    for (i = 0; fmt[i]; i++) {
-        switch (fmt[i]) {
-        case 'b': {
-            uint8_t val = va_arg(ap, int);
-            offset += pdu_pack(pdu, offset, &val, sizeof(val));
-            break;
-        }
-        case 'w': {
-            uint16_t val;
-            cpu_to_le16w(&val, va_arg(ap, int));
-            offset += pdu_pack(pdu, offset, &val, sizeof(val));
-            break;
-        }
-        case 'd': {
-            uint32_t val;
-            cpu_to_le32w(&val, va_arg(ap, uint32_t));
-            offset += pdu_pack(pdu, offset, &val, sizeof(val));
-            break;
-        }
-        case 'q': {
-            uint64_t val;
-            cpu_to_le64w(&val, va_arg(ap, uint64_t));
-            offset += pdu_pack(pdu, offset, &val, sizeof(val));
-            break;
-        }
-        case 's': {
-            V9fsString *str = va_arg(ap, V9fsString *);
-            offset += pdu_marshal(pdu, offset, "w", str->size);
-            offset += pdu_pack(pdu, offset, str->data, str->size);
-            break;
-        }
-        case 'Q': {
-            V9fsQID *qidp = va_arg(ap, V9fsQID *);
-            offset += pdu_marshal(pdu, offset, "bdq",
-                        qidp->type, qidp->version, qidp->path);
-            break;
-        }
-        case 'S': {
-            V9fsStat *statp = va_arg(ap, V9fsStat *);
-            offset += pdu_marshal(pdu, offset, "wwdQdddqsssssddd",
-                        statp->size, statp->type, statp->dev,
-                        &statp->qid, statp->mode, statp->atime,
-                        statp->mtime, statp->length, &statp->name,
-                        &statp->uid, &statp->gid, &statp->muid,
-                        &statp->extension, statp->n_uid,
-                        statp->n_gid, statp->n_muid);
-            break;
-        }
-        case 'A': {
-            V9fsStatDotl *statp = va_arg(ap, V9fsStatDotl *);
-            offset += pdu_marshal(pdu, offset, "qQdddqqqqqqqqqqqqqqq",
-                        statp->st_result_mask,
-                        &statp->qid, statp->st_mode,
-                        statp->st_uid, statp->st_gid,
-                        statp->st_nlink, statp->st_rdev,
-                        statp->st_size, statp->st_blksize, statp->st_blocks,
-                        statp->st_atime_sec, statp->st_atime_nsec,
-                        statp->st_mtime_sec, statp->st_mtime_nsec,
-                        statp->st_ctime_sec, statp->st_ctime_nsec,
-                        statp->st_btime_sec, statp->st_btime_nsec,
-                        statp->st_gen, statp->st_data_version);
-            break;
-        }
-        default:
-            break;
-        }
-    }
-    va_end(ap);
-
-    return offset - old_offset;
-}
-
+/*
+ * We don't do error checking for pdu_marshal/unmarshal here
+ * because we always expect to have enough space to encode
+ * error details
+ */
 static void complete_pdu(V9fsState *s, V9fsPDU *pdu, ssize_t len)
 {
     int8_t id = pdu->id + 1; /* Response */
@@ -946,6 +707,15 @@ static int donttouch_stat(V9fsStat *stat)
     return 0;
 }
 
+static void v9fs_stat_init(V9fsStat *stat)
+{
+    v9fs_string_init(&stat->name);
+    v9fs_string_init(&stat->uid);
+    v9fs_string_init(&stat->gid);
+    v9fs_string_init(&stat->muid);
+    v9fs_string_init(&stat->extension);
+}
+
 static void v9fs_stat_free(V9fsStat *stat)
 {
     v9fs_string_free(&stat->name);
@@ -1130,12 +900,18 @@ static inline bool is_ro_export(FsContext *ctx)
 
 static void v9fs_version(void *opaque)
 {
+    ssize_t err;
     V9fsPDU *pdu = opaque;
     V9fsState *s = pdu->s;
     V9fsString version;
     size_t offset = 7;
 
-    pdu_unmarshal(pdu, offset, "ds", &s->msize, &version);
+    v9fs_string_init(&version);
+    err = pdu_unmarshal(pdu, offset, "ds", &s->msize, &version);
+    if (err < 0) {
+        offset = err;
+        goto out;
+    }
     trace_v9fs_version(pdu->tag, pdu->id, s->msize, version.data);
 
     virtfs_reset(pdu);
@@ -1148,11 +924,15 @@ static void v9fs_version(void *opaque)
         v9fs_string_sprintf(&version, "unknown");
     }
 
-    offset += pdu_marshal(pdu, offset, "ds", s->msize, &version);
+    err = pdu_marshal(pdu, offset, "ds", s->msize, &version);
+    if (err < 0) {
+        offset = err;
+        goto out;
+    }
+    offset += err;
     trace_v9fs_version_return(pdu->tag, pdu->id, s->msize, version.data);
-
+out:
     complete_pdu(s, pdu, offset);
-
     v9fs_string_free(&version);
     return;
 }
@@ -1168,7 +948,13 @@ static void v9fs_attach(void *opaque)
     V9fsQID qid;
     ssize_t err;
 
-    pdu_unmarshal(pdu, offset, "ddssd", &fid, &afid, &uname, &aname, &n_uname);
+    v9fs_string_init(&uname);
+    v9fs_string_init(&aname);
+    err = pdu_unmarshal(pdu, offset, "ddssd", &fid,
+                        &afid, &uname, &aname, &n_uname);
+    if (err < 0) {
+        goto out_nofid;
+    }
     trace_v9fs_attach(pdu->tag, pdu->id, fid, afid, uname.data, aname.data);
 
     fidp = alloc_fid(s, fid);
@@ -1189,8 +975,12 @@ static void v9fs_attach(void *opaque)
         clunk_fid(s, fid);
         goto out;
     }
-    offset += pdu_marshal(pdu, offset, "Q", &qid);
-    err = offset;
+    err = pdu_marshal(pdu, offset, "Q", &qid);
+    if (err < 0) {
+        clunk_fid(s, fid);
+        goto out;
+    }
+    err += offset;
     trace_v9fs_attach_return(pdu->tag, pdu->id,
                              qid.type, qid.version, qid.path);
     s->root_fid = fid;
@@ -1217,7 +1007,10 @@ static void v9fs_stat(void *opaque)
     V9fsPDU *pdu = opaque;
     V9fsState *s = pdu->s;
 
-    pdu_unmarshal(pdu, offset, "d", &fid);
+    err = pdu_unmarshal(pdu, offset, "d", &fid);
+    if (err < 0) {
+        goto out_nofid;
+    }
     trace_v9fs_stat(pdu->tag, pdu->id, fid);
 
     fidp = get_fid(pdu, fid);
@@ -1233,10 +1026,14 @@ static void v9fs_stat(void *opaque)
     if (err < 0) {
         goto out;
     }
-    offset += pdu_marshal(pdu, offset, "wS", 0, &v9stat);
-    err = offset;
+    err = pdu_marshal(pdu, offset, "wS", 0, &v9stat);
+    if (err < 0) {
+        v9fs_stat_free(&v9stat);
+        goto out;
+    }
     trace_v9fs_stat_return(pdu->tag, pdu->id, v9stat.mode,
                            v9stat.atime, v9stat.mtime, v9stat.length);
+    err += offset;
     v9fs_stat_free(&v9stat);
 out:
     put_fid(pdu, fidp);
@@ -1256,7 +1053,10 @@ static void v9fs_getattr(void *opaque)
     V9fsPDU *pdu = opaque;
     V9fsState *s = pdu->s;
 
-    pdu_unmarshal(pdu, offset, "dq", &fid, &request_mask);
+    retval = pdu_unmarshal(pdu, offset, "dq", &fid, &request_mask);
+    if (retval < 0) {
+        goto out_nofid;
+    }
     trace_v9fs_getattr(pdu->tag, pdu->id, fid, request_mask);
 
     fidp = get_fid(pdu, fid);
@@ -1282,8 +1082,11 @@ static void v9fs_getattr(void *opaque)
         }
         v9stat_dotl.st_result_mask |= P9_STATS_GEN;
     }
-    retval = offset;
-    retval += pdu_marshal(pdu, offset, "A", &v9stat_dotl);
+    retval = pdu_marshal(pdu, offset, "A", &v9stat_dotl);
+    if (retval < 0) {
+        goto out;
+    }
+    retval += offset;
     trace_v9fs_getattr_return(pdu->tag, pdu->id, v9stat_dotl.st_result_mask,
                               v9stat_dotl.st_mode, v9stat_dotl.st_uid,
                               v9stat_dotl.st_gid);
@@ -1316,7 +1119,10 @@ static void v9fs_setattr(void *opaque)
     V9fsPDU *pdu = opaque;
     V9fsState *s = pdu->s;
 
-    pdu_unmarshal(pdu, offset, "dI", &fid, &v9iattr);
+    err = pdu_unmarshal(pdu, offset, "dI", &fid, &v9iattr);
+    if (err < 0) {
+        goto out_nofid;
+    }
 
     fidp = get_fid(pdu, fid);
     if (fidp == NULL) {
@@ -1391,10 +1197,20 @@ out_nofid:
 static int v9fs_walk_marshal(V9fsPDU *pdu, uint16_t nwnames, V9fsQID *qids)
 {
     int i;
+    ssize_t err;
     size_t offset = 7;
-    offset += pdu_marshal(pdu, offset, "w", nwnames);
+
+    err = pdu_marshal(pdu, offset, "w", nwnames);
+    if (err < 0) {
+        return err;
+    }
+    offset += err;
     for (i = 0; i < nwnames; i++) {
-        offset += pdu_marshal(pdu, offset, "Q", &qids[i]);
+        err = pdu_marshal(pdu, offset, "Q", &qids[i]);
+        if (err < 0) {
+            return err;
+        }
+        offset += err;
     }
     return offset;
 }
@@ -1415,8 +1231,12 @@ static void v9fs_walk(void *opaque)
     V9fsPDU *pdu = opaque;
     V9fsState *s = pdu->s;
 
-    offset += pdu_unmarshal(pdu, offset, "ddw", &fid,
-                            &newfid, &nwnames);
+    err = pdu_unmarshal(pdu, offset, "ddw", &fid, &newfid, &nwnames);
+    if (err < 0) {
+        complete_pdu(s, pdu, err);
+        return ;
+    }
+    offset += err;
 
     trace_v9fs_walk(pdu->tag, pdu->id, fid, newfid, nwnames);
 
@@ -1424,7 +1244,11 @@ static void v9fs_walk(void *opaque)
         wnames = g_malloc0(sizeof(wnames[0]) * nwnames);
         qids   = g_malloc0(sizeof(qids[0]) * nwnames);
         for (i = 0; i < nwnames; i++) {
-            offset += pdu_unmarshal(pdu, offset, "s", &wnames[i]);
+            err = pdu_unmarshal(pdu, offset, "s", &wnames[i]);
+            if (err < 0) {
+                goto out_nofid;
+            }
+            offset += err;
         }
     } else if (nwnames > P9_MAXWELEM) {
         err = -EINVAL;
@@ -1523,9 +1347,12 @@ static void v9fs_open(void *opaque)
     V9fsState *s = pdu->s;
 
     if (s->proto_version == V9FS_PROTO_2000L) {
-        pdu_unmarshal(pdu, offset, "dd", &fid, &mode);
+        err = pdu_unmarshal(pdu, offset, "dd", &fid, &mode);
     } else {
-        pdu_unmarshal(pdu, offset, "db", &fid, &mode);
+        err = pdu_unmarshal(pdu, offset, "db", &fid, &mode);
+    }
+    if (err < 0) {
+        goto out_nofid;
     }
     trace_v9fs_open(pdu->tag, pdu->id, fid, mode);
 
@@ -1547,8 +1374,11 @@ static void v9fs_open(void *opaque)
             goto out;
         }
         fidp->fid_type = P9_FID_DIR;
-        offset += pdu_marshal(pdu, offset, "Qd", &qid, 0);
-        err = offset;
+        err = pdu_marshal(pdu, offset, "Qd", &qid, 0);
+        if (err < 0) {
+            goto out;
+        }
+        err += offset;
     } else {
         if (s->proto_version == V9FS_PROTO_2000L) {
             flags = get_dotl_openflags(s, mode);
@@ -1577,8 +1407,11 @@ static void v9fs_open(void *opaque)
             fidp->flags |= FID_NON_RECLAIMABLE;
         }
         iounit = get_iounit(pdu, &fidp->path);
-        offset += pdu_marshal(pdu, offset, "Qd", &qid, iounit);
-        err = offset;
+        err = pdu_marshal(pdu, offset, "Qd", &qid, iounit);
+        if (err < 0) {
+            goto out;
+        }
+        err += offset;
     }
     trace_v9fs_open_return(pdu->tag, pdu->id,
                            qid.type, qid.version, qid.path, iounit);
@@ -1601,8 +1434,12 @@ static void v9fs_lcreate(void *opaque)
     int32_t iounit;
     V9fsPDU *pdu = opaque;
 
-    pdu_unmarshal(pdu, offset, "dsddd", &dfid, &name, &flags,
-                  &mode, &gid);
+    v9fs_string_init(&name);
+    err = pdu_unmarshal(pdu, offset, "dsddd", &dfid,
+                        &name, &flags, &mode, &gid);
+    if (err < 0) {
+        goto out_nofid;
+    }
     trace_v9fs_lcreate(pdu->tag, pdu->id, dfid, flags, mode, gid);
 
     fidp = get_fid(pdu, dfid);
@@ -1628,8 +1465,11 @@ static void v9fs_lcreate(void *opaque)
     }
     iounit =  get_iounit(pdu, &fidp->path);
     stat_to_qid(&stbuf, &qid);
-    offset += pdu_marshal(pdu, offset, "Qd", &qid, iounit);
-    err = offset;
+    err = pdu_marshal(pdu, offset, "Qd", &qid, iounit);
+    if (err < 0) {
+        goto out;
+    }
+    err += offset;
     trace_v9fs_lcreate_return(pdu->tag, pdu->id,
                               qid.type, qid.version, qid.path, iounit);
 out:
@@ -1649,7 +1489,10 @@ static void v9fs_fsync(void *opaque)
     V9fsPDU *pdu = opaque;
     V9fsState *s = pdu->s;
 
-    pdu_unmarshal(pdu, offset, "dd", &fid, &datasync);
+    err = pdu_unmarshal(pdu, offset, "dd", &fid, &datasync);
+    if (err < 0) {
+        goto out_nofid;
+    }
     trace_v9fs_fsync(pdu->tag, pdu->id, fid, datasync);
 
     fidp = get_fid(pdu, fid);
@@ -1675,7 +1518,10 @@ static void v9fs_clunk(void *opaque)
     V9fsPDU *pdu = opaque;
     V9fsState *s = pdu->s;
 
-    pdu_unmarshal(pdu, offset, "d", &fid);
+    err = pdu_unmarshal(pdu, offset, "d", &fid);
+    if (err < 0) {
+        goto out_nofid;
+    }
     trace_v9fs_clunk(pdu->tag, pdu->id, fid);
 
     fidp = clunk_fid(s, fid);
@@ -1698,6 +1544,7 @@ out_nofid:
 static int v9fs_xattr_read(V9fsState *s, V9fsPDU *pdu, V9fsFidState *fidp,
                            uint64_t off, uint32_t max_count)
 {
+    ssize_t err;
     size_t offset = 7;
     int read_count;
     int64_t xattr_len;
@@ -1712,10 +1559,18 @@ static int v9fs_xattr_read(V9fsState *s, V9fsPDU *pdu, V9fsFidState *fidp,
          */
         read_count = 0;
     }
-    offset += pdu_marshal(pdu, offset, "d", read_count);
-    offset += pdu_pack(pdu, offset,
-                       ((char *)fidp->fs.xattr.value) + off,
-                       read_count);
+    err = pdu_marshal(pdu, offset, "d", read_count);
+    if (err < 0) {
+        return err;
+    }
+    offset += err;
+    err = v9fs_pack(pdu->elem.in_sg, pdu->elem.in_num, offset,
+                    ((char *)fidp->fs.xattr.value) + off,
+                    read_count);
+    if (err < 0) {
+        return err;
+    }
+    offset += err;
     return offset;
 }
 
@@ -1824,7 +1679,10 @@ static void v9fs_read(void *opaque)
     V9fsPDU *pdu = opaque;
     V9fsState *s = pdu->s;
 
-    pdu_unmarshal(pdu, offset, "dqd", &fid, &off, &max_count);
+    err = pdu_unmarshal(pdu, offset, "dqd", &fid, &off, &max_count);
+    if (err < 0) {
+        goto out_nofid;
+    }
     trace_v9fs_read(pdu->tag, pdu->id, fid, off, max_count);
 
     fidp = get_fid(pdu, fid);
@@ -1842,9 +1700,11 @@ static void v9fs_read(void *opaque)
             err = count;
             goto out;
         }
-        err = offset;
-        err += pdu_marshal(pdu, offset, "d", count);
-        err += count;
+        err = pdu_marshal(pdu, offset, "d", count);
+        if (err < 0) {
+            goto out;
+        }
+        err += offset + count;
     } else if (fidp->fid_type == P9_FID_FILE) {
         QEMUIOVector qiov_full;
         QEMUIOVector qiov;
@@ -1872,9 +1732,11 @@ static void v9fs_read(void *opaque)
                 goto out;
             }
         } while (count < max_count && len > 0);
-        err = offset;
-        err += pdu_marshal(pdu, offset, "d", count);
-        err += count;
+        err = pdu_marshal(pdu, offset, "d", count);
+        if (err < 0) {
+            goto out;
+        }
+        err += offset + count;
         qemu_iovec_destroy(&qiov);
         qemu_iovec_destroy(&qiov_full);
     } else if (fidp->fid_type == P9_FID_XATTR) {
@@ -1946,6 +1808,12 @@ static int v9fs_do_readdir(V9fsPDU *pdu,
         len = pdu_marshal(pdu, 11 + count, "Qqbs",
                           &qid, dent->d_off,
                           dent->d_type, &name);
+        if (len < 0) {
+            v9fs_co_seekdir(pdu, fidp, saved_dir_pos);
+            v9fs_string_free(&name);
+            g_free(dent);
+            return len;
+        }
         count += len;
         v9fs_string_free(&name);
         saved_dir_pos = dent->d_off;
@@ -1969,8 +1837,11 @@ static void v9fs_readdir(void *opaque)
     V9fsPDU *pdu = opaque;
     V9fsState *s = pdu->s;
 
-    pdu_unmarshal(pdu, offset, "dqd", &fid, &initial_offset, &max_count);
-
+    retval = pdu_unmarshal(pdu, offset, "dqd", &fid,
+                           &initial_offset, &max_count);
+    if (retval < 0) {
+        goto out_nofid;
+    }
     trace_v9fs_readdir(pdu->tag, pdu->id, fid, initial_offset, max_count);
 
     fidp = get_fid(pdu, fid);
@@ -1992,9 +1863,11 @@ static void v9fs_readdir(void *opaque)
         retval = count;
         goto out;
     }
-    retval = offset;
-    retval += pdu_marshal(pdu, offset, "d", count);
-    retval += count;
+    retval = pdu_marshal(pdu, offset, "d", count);
+    if (retval < 0) {
+        goto out;
+    }
+    retval += count + offset;
     trace_v9fs_readdir_return(pdu->tag, pdu->id, count, retval);
 out:
     put_fid(pdu, fidp);
@@ -2025,8 +1898,11 @@ static int v9fs_xattr_write(V9fsState *s, V9fsPDU *pdu, V9fsFidState *fidp,
         err = -ENOSPC;
         goto out;
     }
-    offset += pdu_marshal(pdu, offset, "d", write_count);
-    err = offset;
+    err = pdu_marshal(pdu, offset, "d", write_count);
+    if (err < 0) {
+        return err;
+    }
+    err += offset;
     fidp->fs.xattr.copied_len += write_count;
     /*
      * Now copy the content from sg list
@@ -2061,7 +1937,11 @@ static void v9fs_write(void *opaque)
     QEMUIOVector qiov_full;
     QEMUIOVector qiov;
 
-    offset += pdu_unmarshal(pdu, offset, "dqd", &fid, &off, &count);
+    err = pdu_unmarshal(pdu, offset, "dqd", &fid, &off, &count);
+    if (err < 0) {
+        return complete_pdu(s, pdu, err);
+    }
+    offset += err;
     v9fs_init_qiov_from_pdu(&qiov_full, pdu, offset, count, true);
     trace_v9fs_write(pdu->tag, pdu->id, fid, off, count, qiov_full.niov);
 
@@ -2109,8 +1989,11 @@ static void v9fs_write(void *opaque)
     } while (total < count && len > 0);
 
     offset = 7;
-    offset += pdu_marshal(pdu, offset, "d", total);
-    err = offset;
+    err = pdu_marshal(pdu, offset, "d", total);
+    if (err < 0) {
+        goto out;
+    }
+    err += offset;
     trace_v9fs_write_return(pdu->tag, pdu->id, total, err);
 out_qiov:
     qemu_iovec_destroy(&qiov);
@@ -2138,10 +2021,13 @@ static void v9fs_create(void *opaque)
     V9fsPDU *pdu = opaque;
 
     v9fs_path_init(&path);
-
-    pdu_unmarshal(pdu, offset, "dsdbs", &fid, &name,
-                  &perm, &mode, &extension);
-
+    v9fs_string_init(&name);
+    v9fs_string_init(&extension);
+    err = pdu_unmarshal(pdu, offset, "dsdbs", &fid, &name,
+                        &perm, &mode, &extension);
+    if (err < 0) {
+        goto out_nofid;
+    }
     trace_v9fs_create(pdu->tag, pdu->id, fid, name.data, perm, mode);
 
     fidp = get_fid(pdu, fid);
@@ -2272,8 +2158,11 @@ static void v9fs_create(void *opaque)
     }
     iounit = get_iounit(pdu, &fidp->path);
     stat_to_qid(&stbuf, &qid);
-    offset += pdu_marshal(pdu, offset, "Qd", &qid, iounit);
-    err = offset;
+    err = pdu_marshal(pdu, offset, "Qd", &qid, iounit);
+    if (err < 0) {
+        goto out;
+    }
+    err += offset;
     trace_v9fs_create_return(pdu->tag, pdu->id,
                              qid.type, qid.version, qid.path, iounit);
 out:
@@ -2298,7 +2187,12 @@ static void v9fs_symlink(void *opaque)
     gid_t gid;
     size_t offset = 7;
 
-    pdu_unmarshal(pdu, offset, "dssd", &dfid, &name, &symname, &gid);
+    v9fs_string_init(&name);
+    v9fs_string_init(&symname);
+    err = pdu_unmarshal(pdu, offset, "dssd", &dfid, &name, &symname, &gid);
+    if (err < 0) {
+        goto out_nofid;
+    }
     trace_v9fs_symlink(pdu->tag, pdu->id, dfid, name.data, symname.data, gid);
 
     dfidp = get_fid(pdu, dfid);
@@ -2311,8 +2205,11 @@ static void v9fs_symlink(void *opaque)
         goto out;
     }
     stat_to_qid(&stbuf, &qid);
-    offset += pdu_marshal(pdu, offset, "Q", &qid);
-    err = offset;
+    err =  pdu_marshal(pdu, offset, "Q", &qid);
+    if (err < 0) {
+        goto out;
+    }
+    err += offset;
     trace_v9fs_symlink_return(pdu->tag, pdu->id,
                               qid.type, qid.version, qid.path);
 out:
@@ -2325,13 +2222,18 @@ out_nofid:
 
 static void v9fs_flush(void *opaque)
 {
+    ssize_t err;
     int16_t tag;
     size_t offset = 7;
     V9fsPDU *cancel_pdu;
     V9fsPDU *pdu = opaque;
     V9fsState *s = pdu->s;
 
-    pdu_unmarshal(pdu, offset, "w", &tag);
+    err = pdu_unmarshal(pdu, offset, "w", &tag);
+    if (err < 0) {
+        complete_pdu(s, pdu, err);
+        return;
+    }
     trace_v9fs_flush(pdu->tag, pdu->id, tag);
 
     QLIST_FOREACH(cancel_pdu, &s->active_list, next) {
@@ -2362,7 +2264,11 @@ static void v9fs_link(void *opaque)
     size_t offset = 7;
     int err = 0;
 
-    pdu_unmarshal(pdu, offset, "dds", &dfid, &oldfid, &name);
+    v9fs_string_init(&name);
+    err = pdu_unmarshal(pdu, offset, "dds", &dfid, &oldfid, &name);
+    if (err < 0) {
+        goto out_nofid;
+    }
     trace_v9fs_link(pdu->tag, pdu->id, dfid, oldfid, name.data);
 
     dfidp = get_fid(pdu, dfid);
@@ -2396,7 +2302,10 @@ static void v9fs_remove(void *opaque)
     V9fsFidState *fidp;
     V9fsPDU *pdu = opaque;
 
-    pdu_unmarshal(pdu, offset, "d", &fid);
+    err = pdu_unmarshal(pdu, offset, "d", &fid);
+    if (err < 0) {
+        goto out_nofid;
+    }
     trace_v9fs_remove(pdu->tag, pdu->id, fid);
 
     fidp = get_fid(pdu, fid);
@@ -2439,8 +2348,11 @@ static void v9fs_unlinkat(void *opaque)
     V9fsFidState *dfidp;
     V9fsPDU *pdu = opaque;
 
-    pdu_unmarshal(pdu, offset, "dsd", &dfid, &name, &flags);
-
+    v9fs_string_init(&name);
+    err = pdu_unmarshal(pdu, offset, "dsd", &dfid, &name, &flags);
+    if (err < 0) {
+        goto out_nofid;
+    }
     dfidp = get_fid(pdu, dfid);
     if (dfidp == NULL) {
         err = -EINVAL;
@@ -2542,8 +2454,11 @@ static void v9fs_rename(void *opaque)
     V9fsPDU *pdu = opaque;
     V9fsState *s = pdu->s;
 
-    pdu_unmarshal(pdu, offset, "dds", &fid, &newdirfid, &name);
-
+    v9fs_string_init(&name);
+    err = pdu_unmarshal(pdu, offset, "dds", &fid, &newdirfid, &name);
+    if (err < 0) {
+        goto out_nofid;
+    }
     fidp = get_fid(pdu, fid);
     if (fidp == NULL) {
         err = -ENOENT;
@@ -2648,8 +2563,13 @@ static void v9fs_renameat(void *opaque)
     int32_t olddirfid, newdirfid;
     V9fsString old_name, new_name;
 
-    pdu_unmarshal(pdu, offset, "dsds", &olddirfid,
-                  &old_name, &newdirfid, &new_name);
+    v9fs_string_init(&old_name);
+    v9fs_string_init(&new_name);
+    err = pdu_unmarshal(pdu, offset, "dsds", &olddirfid,
+                        &old_name, &newdirfid, &new_name);
+    if (err < 0) {
+        goto out_err;
+    }
 
     v9fs_path_write_lock(s);
     err = v9fs_complete_renameat(pdu, olddirfid,
@@ -2658,6 +2578,8 @@ static void v9fs_renameat(void *opaque)
     if (!err) {
         err = offset;
     }
+
+out_err:
     complete_pdu(s, pdu, err);
     v9fs_string_free(&old_name);
     v9fs_string_free(&new_name);
@@ -2675,7 +2597,11 @@ static void v9fs_wstat(void *opaque)
     V9fsPDU *pdu = opaque;
     V9fsState *s = pdu->s;
 
-    pdu_unmarshal(pdu, offset, "dwS", &fid, &unused, &v9stat);
+    v9fs_stat_init(&v9stat);
+    err = pdu_unmarshal(pdu, offset, "dwS", &fid, &unused, &v9stat);
+    if (err < 0) {
+        goto out_nofid;
+    }
     trace_v9fs_wstat(pdu->tag, pdu->id, fid,
                      v9stat.mode, v9stat.atime, v9stat.mtime);
 
@@ -2809,7 +2735,10 @@ static void v9fs_statfs(void *opaque)
     V9fsPDU *pdu = opaque;
     V9fsState *s = pdu->s;
 
-    pdu_unmarshal(pdu, offset, "d", &fid);
+    retval = pdu_unmarshal(pdu, offset, "d", &fid);
+    if (retval < 0) {
+        goto out_nofid;
+    }
     fidp = get_fid(pdu, fid);
     if (fidp == NULL) {
         retval = -ENOENT;
@@ -2819,8 +2748,11 @@ static void v9fs_statfs(void *opaque)
     if (retval < 0) {
         goto out;
     }
-    retval = offset;
-    retval += v9fs_fill_statfs(s, pdu, &stbuf);
+    retval = v9fs_fill_statfs(s, pdu, &stbuf);
+    if (retval < 0) {
+        goto out;
+    }
+    retval += offset;
 out:
     put_fid(pdu, fidp);
 out_nofid:
@@ -2844,8 +2776,12 @@ static void v9fs_mknod(void *opaque)
     V9fsPDU *pdu = opaque;
     V9fsState *s = pdu->s;
 
-    pdu_unmarshal(pdu, offset, "dsdddd", &fid, &name, &mode,
-                  &major, &minor, &gid);
+    v9fs_string_init(&name);
+    err = pdu_unmarshal(pdu, offset, "dsdddd", &fid, &name, &mode,
+                        &major, &minor, &gid);
+    if (err < 0) {
+        goto out_nofid;
+    }
     trace_v9fs_mknod(pdu->tag, pdu->id, fid, mode, major, minor);
 
     fidp = get_fid(pdu, fid);
@@ -2859,8 +2795,11 @@ static void v9fs_mknod(void *opaque)
         goto out;
     }
     stat_to_qid(&stbuf, &qid);
-    err = offset;
-    err += pdu_marshal(pdu, offset, "Q", &qid);
+    err = pdu_marshal(pdu, offset, "Q", &qid);
+    if (err < 0) {
+        goto out;
+    }
+    err += offset;
     trace_v9fs_mknod_return(pdu->tag, pdu->id,
                             qid.type, qid.version, qid.path);
 out:
@@ -2881,7 +2820,7 @@ out_nofid:
 static void v9fs_lock(void *opaque)
 {
     int8_t status;
-    V9fsFlock *flock;
+    V9fsFlock flock;
     size_t offset = 7;
     struct stat stbuf;
     V9fsFidState *fidp;
@@ -2889,18 +2828,20 @@ static void v9fs_lock(void *opaque)
     V9fsPDU *pdu = opaque;
     V9fsState *s = pdu->s;
 
-    flock = g_malloc(sizeof(*flock));
-    pdu_unmarshal(pdu, offset, "dbdqqds", &fid, &flock->type,
-                  &flock->flags, &flock->start, &flock->length,
-                  &flock->proc_id, &flock->client_id);
-
+    status = P9_LOCK_ERROR;
+    v9fs_string_init(&flock.client_id);
+    err = pdu_unmarshal(pdu, offset, "dbdqqds", &fid, &flock.type,
+                        &flock.flags, &flock.start, &flock.length,
+                        &flock.proc_id, &flock.client_id);
+    if (err < 0) {
+        goto out_nofid;
+    }
     trace_v9fs_lock(pdu->tag, pdu->id, fid,
-                    flock->type, flock->start, flock->length);
+                    flock.type, flock.start, flock.length);
 
-    status = P9_LOCK_ERROR;
 
     /* We support only block flag now (that too ignored currently) */
-    if (flock->flags & ~P9_LOCK_FLAGS_BLOCK) {
+    if (flock.flags & ~P9_LOCK_FLAGS_BLOCK) {
         err = -EINVAL;
         goto out_nofid;
     }
@@ -2917,12 +2858,13 @@ static void v9fs_lock(void *opaque)
 out:
     put_fid(pdu, fidp);
 out_nofid:
-    err = offset;
-    err += pdu_marshal(pdu, offset, "b", status);
+    err = pdu_marshal(pdu, offset, "b", status);
+    if (err > 0) {
+        err += offset;
+    }
     trace_v9fs_lock_return(pdu->tag, pdu->id, status);
     complete_pdu(s, pdu, err);
-    v9fs_string_free(&flock->client_id);
-    g_free(flock);
+    v9fs_string_free(&flock.client_id);
 }
 
 /*
@@ -2934,18 +2876,20 @@ static void v9fs_getlock(void *opaque)
     size_t offset = 7;
     struct stat stbuf;
     V9fsFidState *fidp;
-    V9fsGetlock *glock;
+    V9fsGetlock glock;
     int32_t fid, err = 0;
     V9fsPDU *pdu = opaque;
     V9fsState *s = pdu->s;
 
-    glock = g_malloc(sizeof(*glock));
-    pdu_unmarshal(pdu, offset, "dbqqds", &fid, &glock->type,
-                  &glock->start, &glock->length, &glock->proc_id,
-                  &glock->client_id);
-
+    v9fs_string_init(&glock.client_id);
+    err = pdu_unmarshal(pdu, offset, "dbqqds", &fid, &glock.type,
+                        &glock.start, &glock.length, &glock.proc_id,
+                        &glock.client_id);
+    if (err < 0) {
+        goto out_nofid;
+    }
     trace_v9fs_getlock(pdu->tag, pdu->id, fid,
-                       glock->type, glock->start, glock->length);
+                       glock.type, glock.start, glock.length);
 
     fidp = get_fid(pdu, fid);
     if (fidp == NULL) {
@@ -2956,19 +2900,21 @@ static void v9fs_getlock(void *opaque)
     if (err < 0) {
         goto out;
     }
-    glock->type = P9_LOCK_TYPE_UNLCK;
-    offset += pdu_marshal(pdu, offset, "bqqds", glock->type,
-                          glock->start, glock->length, glock->proc_id,
-                          &glock->client_id);
-    err = offset;
-    trace_v9fs_getlock_return(pdu->tag, pdu->id, glock->type, glock->start,
-                              glock->length, glock->proc_id);
+    glock.type = P9_LOCK_TYPE_UNLCK;
+    err = pdu_marshal(pdu, offset, "bqqds", glock.type,
+                          glock.start, glock.length, glock.proc_id,
+                          &glock.client_id);
+    if (err < 0) {
+        goto out;
+    }
+    err += offset;
+    trace_v9fs_getlock_return(pdu->tag, pdu->id, glock.type, glock.start,
+                              glock.length, glock.proc_id);
 out:
     put_fid(pdu, fidp);
 out_nofid:
     complete_pdu(s, pdu, err);
-    v9fs_string_free(&glock->client_id);
-    g_free(glock);
+    v9fs_string_free(&glock.client_id);
 }
 
 static void v9fs_mkdir(void *opaque)
@@ -2984,8 +2930,11 @@ static void v9fs_mkdir(void *opaque)
     int mode;
     int err = 0;
 
-    pdu_unmarshal(pdu, offset, "dsdd", &fid, &name, &mode, &gid);
-
+    v9fs_string_init(&name);
+    err = pdu_unmarshal(pdu, offset, "dsdd", &fid, &name, &mode, &gid);
+    if (err < 0) {
+        goto out_nofid;
+    }
     trace_v9fs_mkdir(pdu->tag, pdu->id, fid, name.data, mode, gid);
 
     fidp = get_fid(pdu, fid);
@@ -2998,8 +2947,11 @@ static void v9fs_mkdir(void *opaque)
         goto out;
     }
     stat_to_qid(&stbuf, &qid);
-    offset += pdu_marshal(pdu, offset, "Q", &qid);
-    err = offset;
+    err = pdu_marshal(pdu, offset, "Q", &qid);
+    if (err < 0) {
+        goto out;
+    }
+    err += offset;
     trace_v9fs_mkdir_return(pdu->tag, pdu->id,
                             qid.type, qid.version, qid.path, err);
 out:
@@ -3021,7 +2973,11 @@ static void v9fs_xattrwalk(void *opaque)
     V9fsPDU *pdu = opaque;
     V9fsState *s = pdu->s;
 
-    pdu_unmarshal(pdu, offset, "dds", &fid, &newfid, &name);
+    v9fs_string_init(&name);
+    err = pdu_unmarshal(pdu, offset, "dds", &fid, &newfid, &name);
+    if (err < 0) {
+        goto out_nofid;
+    }
     trace_v9fs_xattrwalk(pdu->tag, pdu->id, fid, newfid, name.data);
 
     file_fidp = get_fid(pdu, fid);
@@ -3035,7 +2991,7 @@ static void v9fs_xattrwalk(void *opaque)
         goto out;
     }
     v9fs_path_copy(&xattr_fidp->path, &file_fidp->path);
-    if (name.data[0] == 0) {
+    if (name.data == NULL) {
         /*
          * listxattr request. Get the size first
          */
@@ -3061,8 +3017,11 @@ static void v9fs_xattrwalk(void *opaque)
                 goto out;
             }
         }
-        offset += pdu_marshal(pdu, offset, "q", size);
-        err = offset;
+        err = pdu_marshal(pdu, offset, "q", size);
+        if (err < 0) {
+            goto out;
+        }
+        err += offset;
     } else {
         /*
          * specific xattr fid. We check for xattr
@@ -3091,8 +3050,11 @@ static void v9fs_xattrwalk(void *opaque)
                 goto out;
             }
         }
-        offset += pdu_marshal(pdu, offset, "q", size);
-        err = offset;
+        err = pdu_marshal(pdu, offset, "q", size);
+        if (err < 0) {
+            goto out;
+        }
+        err += offset;
     }
     trace_v9fs_xattrwalk_return(pdu->tag, pdu->id, size);
 out:
@@ -3118,8 +3080,11 @@ static void v9fs_xattrcreate(void *opaque)
     V9fsPDU *pdu = opaque;
     V9fsState *s = pdu->s;
 
-    pdu_unmarshal(pdu, offset, "dsqd",
-                  &fid, &name, &size, &flags);
+    v9fs_string_init(&name);
+    err = pdu_unmarshal(pdu, offset, "dsqd", &fid, &name, &size, &flags);
+    if (err < 0) {
+        goto out_nofid;
+    }
     trace_v9fs_xattrcreate(pdu->tag, pdu->id, fid, name.data, size, flags);
 
     file_fidp = get_fid(pdu, fid);
@@ -3156,7 +3121,10 @@ static void v9fs_readlink(void *opaque)
     int err = 0;
     V9fsFidState *fidp;
 
-    pdu_unmarshal(pdu, offset, "d", &fid);
+    err = pdu_unmarshal(pdu, offset, "d", &fid);
+    if (err < 0) {
+        goto out_nofid;
+    }
     trace_v9fs_readlink(pdu->tag, pdu->id, fid);
     fidp = get_fid(pdu, fid);
     if (fidp == NULL) {
@@ -3169,8 +3137,12 @@ static void v9fs_readlink(void *opaque)
     if (err < 0) {
         goto out;
     }
-    offset += pdu_marshal(pdu, offset, "s", &target);
-    err = offset;
+    err = pdu_marshal(pdu, offset, "s", &target);
+    if (err < 0) {
+        v9fs_string_free(&target);
+        goto out;
+    }
+    err += offset;
     trace_v9fs_readlink_return(pdu->tag, pdu->id, target.data);
     v9fs_string_free(&target);
 out:
diff --git a/hw/9pfs/virtio-9p.h b/hw/9pfs/virtio-9p.h
index 19a797b727..579794404b 100644
--- a/hw/9pfs/virtio-9p.h
+++ b/hw/9pfs/virtio-9p.h
@@ -8,9 +8,11 @@
 #include <sys/resource.h>
 #include "hw/virtio.h"
 #include "fsdev/file-op-9p.h"
+#include "fsdev/virtio-9p-marshal.h"
 #include "qemu-thread.h"
 #include "qemu-coroutine.h"
 
+
 /* The feature bitmap for virtio 9P */
 /* The mount point is specified in a config variable */
 #define VIRTIO_9P_MOUNT_TAG 0
@@ -154,40 +156,6 @@ struct V9fsPDU
 
 typedef struct V9fsFidState V9fsFidState;
 
-typedef struct V9fsString
-{
-    uint16_t size;
-    char *data;
-} V9fsString;
-
-typedef struct V9fsQID
-{
-    int8_t type;
-    int32_t version;
-    int64_t path;
-} V9fsQID;
-
-typedef struct V9fsStat
-{
-    int16_t size;
-    int16_t type;
-    int32_t dev;
-    V9fsQID qid;
-    int32_t mode;
-    int32_t atime;
-    int32_t mtime;
-    int64_t length;
-    V9fsString name;
-    V9fsString uid;
-    V9fsString gid;
-    V9fsString muid;
-    /* 9p2000.u */
-    V9fsString extension;
-   int32_t n_uid;
-    int32_t n_gid;
-    int32_t n_muid;
-} V9fsStat;
-
 enum {
     P9_FID_NONE = 0,
     P9_FID_FILE,
@@ -267,29 +235,6 @@ typedef struct V9fsStatState {
     struct stat stbuf;
 } V9fsStatState;
 
-typedef struct V9fsStatDotl {
-    uint64_t st_result_mask;
-    V9fsQID qid;
-    uint32_t st_mode;
-    uint32_t st_uid;
-    uint32_t st_gid;
-    uint64_t st_nlink;
-    uint64_t st_rdev;
-    uint64_t st_size;
-    uint64_t st_blksize;
-    uint64_t st_blocks;
-    uint64_t st_atime_sec;
-    uint64_t st_atime_nsec;
-    uint64_t st_mtime_sec;
-    uint64_t st_mtime_nsec;
-    uint64_t st_ctime_sec;
-    uint64_t st_ctime_nsec;
-    uint64_t st_btime_sec;
-    uint64_t st_btime_nsec;
-    uint64_t st_gen;
-    uint64_t st_data_version;
-} V9fsStatDotl;
-
 typedef struct V9fsOpenState {
     V9fsPDU *pdu;
     size_t offset;
@@ -332,19 +277,6 @@ typedef struct V9fsWriteState {
     int cnt;
 } V9fsWriteState;
 
-typedef struct V9fsIattr
-{
-    int32_t valid;
-    int32_t mode;
-    int32_t uid;
-    int32_t gid;
-    int64_t size;
-    int64_t atime_sec;
-    int64_t atime_nsec;
-    int64_t mtime_sec;
-    int64_t mtime_nsec;
-} V9fsIattr;
-
 struct virtio_9p_config
 {
     /* number of characters in tag */
@@ -459,14 +391,15 @@ static inline uint8_t v9fs_request_cancelled(V9fsPDU *pdu)
 extern void handle_9p_output(VirtIODevice *vdev, VirtQueue *vq);
 extern void virtio_9p_set_fd_limit(void);
 extern void v9fs_reclaim_fd(V9fsPDU *pdu);
-extern void v9fs_string_init(V9fsString *str);
-extern void v9fs_string_free(V9fsString *str);
-extern void v9fs_string_null(V9fsString *str);
-extern void v9fs_string_sprintf(V9fsString *str, const char *fmt, ...);
-extern void v9fs_string_copy(V9fsString *lhs, V9fsString *rhs);
 extern void v9fs_path_init(V9fsPath *path);
 extern void v9fs_path_free(V9fsPath *path);
 extern void v9fs_path_copy(V9fsPath *lhs, V9fsPath *rhs);
 extern int v9fs_name_to_path(V9fsState *s, V9fsPath *dirpath,
                              const char *name, V9fsPath *path);
+
+#define pdu_marshal(pdu, offset, fmt, args...)  \
+    v9fs_marshal(pdu->elem.in_sg, pdu->elem.in_num, offset, 1, fmt, ##args)
+#define pdu_unmarshal(pdu, offset, fmt, args...)  \
+    v9fs_unmarshal(pdu->elem.out_sg, pdu->elem.out_num, offset, 1, fmt, ##args)
+
 #endif