Merge remote-tracking branch 'aneesh/for-upstream-7' into staging

9 files changed, 842 insertions, 136 deletions

diff --git a/hw/9pfs/codir.c b/hw/9pfs/codir.c
index 72732e7..9b6d47d 100644
--- a/hw/9pfs/codir.c
+++ b/hw/9pfs/codir.c
@@ -29,7 +29,7 @@ int v9fs_co_readdir_r(V9fsPDU *pdu, V9fsFidState *fidp, struct dirent *dent,
     v9fs_co_run_in_worker(
         {
             errno = 0;
-            err = s->ops->readdir_r(&s->ctx, fidp->fs.dir, dent, result);
+            err = s->ops->readdir_r(&s->ctx, &fidp->fs, dent, result);
             if (!*result && errno) {
                 err = -errno;
             } else {
@@ -49,7 +49,7 @@ off_t v9fs_co_telldir(V9fsPDU *pdu, V9fsFidState *fidp)
     }
     v9fs_co_run_in_worker(
         {
-            err = s->ops->telldir(&s->ctx, fidp->fs.dir);
+            err = s->ops->telldir(&s->ctx, &fidp->fs);
             if (err < 0) {
                 err = -errno;
             }
@@ -65,7 +65,7 @@ void v9fs_co_seekdir(V9fsPDU *pdu, V9fsFidState *fidp, off_t offset)
     }
     v9fs_co_run_in_worker(
         {
-            s->ops->seekdir(&s->ctx, fidp->fs.dir, offset);
+            s->ops->seekdir(&s->ctx, &fidp->fs, offset);
         });
 }
 
@@ -77,7 +77,7 @@ void v9fs_co_rewinddir(V9fsPDU *pdu, V9fsFidState *fidp)
     }
     v9fs_co_run_in_worker(
         {
-            s->ops->rewinddir(&s->ctx, fidp->fs.dir);
+            s->ops->rewinddir(&s->ctx, &fidp->fs);
         });
 }
 
@@ -129,8 +129,8 @@ int v9fs_co_opendir(V9fsPDU *pdu, V9fsFidState *fidp)
     v9fs_path_read_lock(s);
     v9fs_co_run_in_worker(
         {
-            fidp->fs.dir = s->ops->opendir(&s->ctx, &fidp->path);
-            if (!fidp->fs.dir) {
+            err = s->ops->opendir(&s->ctx, &fidp->path, &fidp->fs);
+            if (err < 0) {
                 err = -errno;
             } else {
                 err = 0;
@@ -146,7 +146,7 @@ int v9fs_co_opendir(V9fsPDU *pdu, V9fsFidState *fidp)
     return err;
 }
 
-int v9fs_co_closedir(V9fsPDU *pdu, DIR *dir)
+int v9fs_co_closedir(V9fsPDU *pdu, V9fsFidOpenState *fs)
 {
     int err;
     V9fsState *s = pdu->s;
@@ -156,7 +156,7 @@ int v9fs_co_closedir(V9fsPDU *pdu, DIR *dir)
     }
     v9fs_co_run_in_worker(
         {
-            err = s->ops->closedir(&s->ctx, dir);
+            err = s->ops->closedir(&s->ctx, fs);
             if (err < 0) {
                 err = -errno;
             }
diff --git a/hw/9pfs/cofile.c b/hw/9pfs/cofile.c
index 692811e..586b038 100644
--- a/hw/9pfs/cofile.c
+++ b/hw/9pfs/cofile.c
@@ -61,7 +61,7 @@ int v9fs_co_lstat(V9fsPDU *pdu, V9fsPath *path, struct stat *stbuf)
     return err;
 }
 
-int v9fs_co_fstat(V9fsPDU *pdu, int fd, struct stat *stbuf)
+int v9fs_co_fstat(V9fsPDU *pdu, V9fsFidState *fidp, struct stat *stbuf)
 {
     int err;
     V9fsState *s = pdu->s;
@@ -71,7 +71,7 @@ int v9fs_co_fstat(V9fsPDU *pdu, int fd, struct stat *stbuf)
     }
     v9fs_co_run_in_worker(
         {
-            err = s->ops->fstat(&s->ctx, fd, stbuf);
+            err = s->ops->fstat(&s->ctx, &fidp->fs, stbuf);
             if (err < 0) {
                 err = -errno;
             }
@@ -90,8 +90,8 @@ int v9fs_co_open(V9fsPDU *pdu, V9fsFidState *fidp, int flags)
     v9fs_path_read_lock(s);
     v9fs_co_run_in_worker(
         {
-            fidp->fs.fd = s->ops->open(&s->ctx, &fidp->path, flags);
-            if (fidp->fs.fd == -1) {
+            err = s->ops->open(&s->ctx, &fidp->path, flags, &fidp->fs);
+            if (err == -1) {
                 err = -errno;
             } else {
                 err = 0;
@@ -130,9 +130,9 @@ int v9fs_co_open2(V9fsPDU *pdu, V9fsFidState *fidp, V9fsString *name, gid_t gid,
     v9fs_path_read_lock(s);
     v9fs_co_run_in_worker(
         {
-            fidp->fs.fd = s->ops->open2(&s->ctx, &fidp->path,
-                                        name->data, flags, &cred);
-            if (fidp->fs.fd == -1) {
+            err = s->ops->open2(&s->ctx, &fidp->path,
+                                name->data, flags, &cred, &fidp->fs);
+            if (err < 0) {
                 err = -errno;
             } else {
                 v9fs_path_init(&path);
@@ -141,12 +141,12 @@ int v9fs_co_open2(V9fsPDU *pdu, V9fsFidState *fidp, V9fsString *name, gid_t gid,
                     err = s->ops->lstat(&s->ctx, &path, stbuf);
                     if (err < 0) {
                         err = -errno;
-                        s->ops->close(&s->ctx, fidp->fs.fd);
+                        s->ops->close(&s->ctx, &fidp->fs);
                     } else {
                         v9fs_path_copy(&fidp->path, &path);
                     }
                 } else {
-                    s->ops->close(&s->ctx, fidp->fs.fd);
+                    s->ops->close(&s->ctx, &fidp->fs);
                 }
                 v9fs_path_free(&path);
             }
@@ -161,7 +161,7 @@ int v9fs_co_open2(V9fsPDU *pdu, V9fsFidState *fidp, V9fsString *name, gid_t gid,
     return err;
 }
 
-int v9fs_co_close(V9fsPDU *pdu, int fd)
+int v9fs_co_close(V9fsPDU *pdu, V9fsFidOpenState *fs)
 {
     int err;
     V9fsState *s = pdu->s;
@@ -171,7 +171,7 @@ int v9fs_co_close(V9fsPDU *pdu, int fd)
     }
     v9fs_co_run_in_worker(
         {
-            err = s->ops->close(&s->ctx, fd);
+            err = s->ops->close(&s->ctx, fs);
             if (err < 0) {
                 err = -errno;
             }
@@ -184,16 +184,15 @@ int v9fs_co_close(V9fsPDU *pdu, int fd)
 
 int v9fs_co_fsync(V9fsPDU *pdu, V9fsFidState *fidp, int datasync)
 {
-    int fd, err;
+    int err;
     V9fsState *s = pdu->s;
 
     if (v9fs_request_cancelled(pdu)) {
         return -EINTR;
     }
-    fd = fidp->fs.fd;
     v9fs_co_run_in_worker(
         {
-            err = s->ops->fsync(&s->ctx, fd, datasync);
+            err = s->ops->fsync(&s->ctx, &fidp->fs, datasync);
             if (err < 0) {
                 err = -errno;
             }
@@ -226,16 +225,15 @@ int v9fs_co_link(V9fsPDU *pdu, V9fsFidState *oldfid,
 int v9fs_co_pwritev(V9fsPDU *pdu, V9fsFidState *fidp,
                     struct iovec *iov, int iovcnt, int64_t offset)
 {
-    int fd, err;
+    int err;
     V9fsState *s = pdu->s;
 
     if (v9fs_request_cancelled(pdu)) {
         return -EINTR;
     }
-    fd = fidp->fs.fd;
     v9fs_co_run_in_worker(
         {
-            err = s->ops->pwritev(&s->ctx, fd, iov, iovcnt, offset);
+            err = s->ops->pwritev(&s->ctx, &fidp->fs, iov, iovcnt, offset);
             if (err < 0) {
                 err = -errno;
             }
@@ -246,16 +244,15 @@ int v9fs_co_pwritev(V9fsPDU *pdu, V9fsFidState *fidp,
 int v9fs_co_preadv(V9fsPDU *pdu, V9fsFidState *fidp,
                    struct iovec *iov, int iovcnt, int64_t offset)
 {
-    int fd, err;
+    int err;
     V9fsState *s = pdu->s;
 
     if (v9fs_request_cancelled(pdu)) {
         return -EINTR;
     }
-    fd = fidp->fs.fd;
     v9fs_co_run_in_worker(
         {
-            err = s->ops->preadv(&s->ctx, fd, iov, iovcnt, offset);
+            err = s->ops->preadv(&s->ctx, &fidp->fs, iov, iovcnt, offset);
             if (err < 0) {
                 err = -errno;
             }
diff --git a/hw/9pfs/virtio-9p-coth.h b/hw/9pfs/virtio-9p-coth.h
index ca96b9c..c4b74b0 100644
--- a/hw/9pfs/virtio-9p-coth.h
+++ b/hw/9pfs/virtio-9p-coth.h
@@ -80,7 +80,7 @@ extern int v9fs_co_rename(V9fsPDU *, V9fsPath *, V9fsPath *);
 extern int v9fs_co_unlinkat(V9fsPDU *, V9fsPath *, V9fsString *, int flags);
 extern int v9fs_co_renameat(V9fsPDU *, V9fsPath *, V9fsString *,
                             V9fsPath *, V9fsString *);
-extern int v9fs_co_fstat(V9fsPDU *, int, struct stat *);
+extern int v9fs_co_fstat(V9fsPDU *, V9fsFidState *, struct stat *);
 extern int v9fs_co_opendir(V9fsPDU *, V9fsFidState *);
 extern int v9fs_co_open(V9fsPDU *, V9fsFidState *, int);
 extern int v9fs_co_open2(V9fsPDU *, V9fsFidState *, V9fsString *,
@@ -88,8 +88,8 @@ extern int v9fs_co_open2(V9fsPDU *, V9fsFidState *, V9fsString *,
 extern int v9fs_co_lsetxattr(V9fsPDU *, V9fsPath *, V9fsString *,
                              void *, size_t, int);
 extern int v9fs_co_lremovexattr(V9fsPDU *, V9fsPath *, V9fsString *);
-extern int v9fs_co_closedir(V9fsPDU *, DIR *);
-extern int v9fs_co_close(V9fsPDU *, int);
+extern int v9fs_co_closedir(V9fsPDU *, V9fsFidOpenState *);
+extern int v9fs_co_close(V9fsPDU *, V9fsFidOpenState *);
 extern int v9fs_co_fsync(V9fsPDU *, V9fsFidState *, int);
 extern int v9fs_co_symlink(V9fsPDU *, V9fsFidState *, V9fsString *,
                            const char *, gid_t, struct stat *);
diff --git a/hw/9pfs/virtio-9p-handle.c b/hw/9pfs/virtio-9p-handle.c
index 98809f1..c38e0e7 100644
--- a/hw/9pfs/virtio-9p-handle.c
+++ b/hw/9pfs/virtio-9p-handle.c
@@ -133,81 +133,91 @@ static ssize_t handle_readlink(FsContext *fs_ctx, V9fsPath *fs_path,
     return ret;
 }
 
-static int handle_close(FsContext *ctx, int fd)
+static int handle_close(FsContext *ctx, V9fsFidOpenState *fs)
 {
-    return close(fd);
+    return close(fs->fd);
 }
 
-static int handle_closedir(FsContext *ctx, DIR *dir)
+static int handle_closedir(FsContext *ctx, V9fsFidOpenState *fs)
 {
-    return closedir(dir);
+    return closedir(fs->dir);
 }
 
-static int handle_open(FsContext *ctx, V9fsPath *fs_path, int flags)
+static int handle_open(FsContext *ctx, V9fsPath *fs_path,
+                       int flags, V9fsFidOpenState *fs)
 {
     struct handle_data *data = (struct handle_data *)ctx->private;
 
-    return open_by_handle(data->mountfd, fs_path->data, flags);
+    fs->fd = open_by_handle(data->mountfd, fs_path->data, flags);
+    return fs->fd;
 }
 
-static DIR *handle_opendir(FsContext *ctx, V9fsPath *fs_path)
+static int handle_opendir(FsContext *ctx,
+                          V9fsPath *fs_path, V9fsFidOpenState *fs)
 {
-    int fd;
-    fd = handle_open(ctx, fs_path, O_DIRECTORY);
-    if (fd < 0) {
-        return NULL;
+    int ret;
+    ret = handle_open(ctx, fs_path, O_DIRECTORY, fs);
+    if (ret < 0) {
+        return -1;
     }
-    return fdopendir(fd);
+    fs->dir = fdopendir(ret);
+    if (!fs->dir) {
+        return -1;
+    }
+    return 0;
 }
 
-static void handle_rewinddir(FsContext *ctx, DIR *dir)
+static void handle_rewinddir(FsContext *ctx, V9fsFidOpenState *fs)
 {
-    return rewinddir(dir);
+    return rewinddir(fs->dir);
 }
 
-static off_t handle_telldir(FsContext *ctx, DIR *dir)
+static off_t handle_telldir(FsContext *ctx, V9fsFidOpenState *fs)
 {
-    return telldir(dir);
+    return telldir(fs->dir);
 }
 
-static int handle_readdir_r(FsContext *ctx, DIR *dir, struct dirent *entry,
+static int handle_readdir_r(FsContext *ctx, V9fsFidOpenState *fs,
+                            struct dirent *entry,
                             struct dirent **result)
 {
-    return readdir_r(dir, entry, result);
+    return readdir_r(fs->dir, entry, result);
 }
 
-static void handle_seekdir(FsContext *ctx, DIR *dir, off_t off)
+static void handle_seekdir(FsContext *ctx, V9fsFidOpenState *fs, off_t off)
 {
-    return seekdir(dir, off);
+    return seekdir(fs->dir, off);
 }
 
-static ssize_t handle_preadv(FsContext *ctx, int fd, const struct iovec *iov,
+static ssize_t handle_preadv(FsContext *ctx, V9fsFidOpenState *fs,
+                             const struct iovec *iov,
                              int iovcnt, off_t offset)
 {
 #ifdef CONFIG_PREADV
-    return preadv(fd, iov, iovcnt, offset);
+    return preadv(fs->fd, iov, iovcnt, offset);
 #else
-    int err = lseek(fd, offset, SEEK_SET);
+    int err = lseek(fs->fd, offset, SEEK_SET);
     if (err == -1) {
         return err;
     } else {
-        return readv(fd, iov, iovcnt);
+        return readv(fs->fd, iov, iovcnt);
     }
 #endif
 }
 
-static ssize_t handle_pwritev(FsContext *ctx, int fd, const struct iovec *iov,
+static ssize_t handle_pwritev(FsContext *ctx, V9fsFidOpenState *fs,
+                              const struct iovec *iov,
                               int iovcnt, off_t offset)
 {
     ssize_t ret;
 #ifdef CONFIG_PREADV
-    ret = pwritev(fd, iov, iovcnt, offset);
+    ret = pwritev(fs->fd, iov, iovcnt, offset);
 #else
-    int err = lseek(fd, offset, SEEK_SET);
+    int err = lseek(fs->fd, offset, SEEK_SET);
     if (err == -1) {
         return err;
     } else {
-        ret = writev(fd, iov, iovcnt);
+        ret = writev(fs->fd, iov, iovcnt);
     }
 #endif
 #ifdef CONFIG_SYNC_FILE_RANGE
@@ -217,7 +227,7 @@ static ssize_t handle_pwritev(FsContext *ctx, int fd, const struct iovec *iov,
          * We want to ensure that we don't leave dirty pages in the cache
          * after write when writeout=immediate is sepcified.
          */
-        sync_file_range(fd, offset, ret,
+        sync_file_range(fs->fd, offset, ret,
                         SYNC_FILE_RANGE_WAIT_BEFORE | SYNC_FILE_RANGE_WRITE);
     }
 #endif
@@ -274,13 +284,14 @@ static int handle_mkdir(FsContext *fs_ctx, V9fsPath *dir_path,
     return ret;
 }
 
-static int handle_fstat(FsContext *fs_ctx, int fd, struct stat *stbuf)
+static int handle_fstat(FsContext *fs_ctx, V9fsFidOpenState *fs,
+                        struct stat *stbuf)
 {
-    return fstat(fd, stbuf);
+    return fstat(fs->fd, stbuf);
 }
 
 static int handle_open2(FsContext *fs_ctx, V9fsPath *dir_path, const char *name,
-                       int flags, FsCred *credp)
+                        int flags, FsCred *credp, V9fsFidOpenState *fs)
 {
     int ret;
     int dirfd, fd;
@@ -296,6 +307,8 @@ static int handle_open2(FsContext *fs_ctx, V9fsPath *dir_path, const char *name,
         if (ret < 0) {
             close(fd);
             fd = ret;
+        } else {
+            fs->fd = fd;
         }
     }
     close(dirfd);
@@ -411,12 +424,12 @@ static int handle_remove(FsContext *ctx, const char *path)
     return -1;
 }
 
-static int handle_fsync(FsContext *ctx, int fd, int datasync)
+static int handle_fsync(FsContext *ctx, V9fsFidOpenState *fs, int datasync)
 {
     if (datasync) {
-        return qemu_fdatasync(fd);
+        return qemu_fdatasync(fs->fd);
     } else {
-        return fsync(fd);
+        return fsync(fs->fd);
     }
 }
 
@@ -575,7 +588,8 @@ static int handle_unlinkat(FsContext *ctx, V9fsPath *dir,
 static int handle_ioc_getversion(FsContext *ctx, V9fsPath *path,
                                  mode_t st_mode, uint64_t *st_gen)
 {
-    int err, fd;
+    int err;
+    V9fsFidOpenState fid_open;
 
     /*
      * Do not try to open special files like device nodes, fifos etc
@@ -584,12 +598,12 @@ static int handle_ioc_getversion(FsContext *ctx, V9fsPath *path,
     if (!S_ISREG(st_mode) && !S_ISDIR(st_mode)) {
             return 0;
     }
-    fd = handle_open(ctx, path, O_RDONLY);
-    if (fd < 0) {
-        return fd;
+    err = handle_open(ctx, path, O_RDONLY, &fid_open);
+    if (err < 0) {
+        return err;
     }
-    err = ioctl(fd, FS_IOC_GETVERSION, st_gen);
-    handle_close(ctx, fd);
+    err = ioctl(fid_open.fd, FS_IOC_GETVERSION, st_gen);
+    handle_close(ctx, &fid_open);
     return err;
 }
 
diff --git a/hw/9pfs/virtio-9p-local.c b/hw/9pfs/virtio-9p-local.c
index d561de8..782dc0a 100644
--- a/hw/9pfs/virtio-9p-local.c
+++ b/hw/9pfs/virtio-9p-local.c
@@ -156,81 +156,91 @@ static ssize_t local_readlink(FsContext *fs_ctx, V9fsPath *fs_path,
     return tsize;
 }
 
-static int local_close(FsContext *ctx, int fd)
+static int local_close(FsContext *ctx, V9fsFidOpenState *fs)
 {
-    return close(fd);
+    return close(fs->fd);
 }
 
-static int local_closedir(FsContext *ctx, DIR *dir)
+static int local_closedir(FsContext *ctx, V9fsFidOpenState *fs)
 {
-    return closedir(dir);
+    return closedir(fs->dir);
 }
 
-static int local_open(FsContext *ctx, V9fsPath *fs_path, int flags)
+static int local_open(FsContext *ctx, V9fsPath *fs_path,
+                      int flags, V9fsFidOpenState *fs)
 {
     char buffer[PATH_MAX];
     char *path = fs_path->data;
 
-    return open(rpath(ctx, path, buffer), flags);
+    fs->fd = open(rpath(ctx, path, buffer), flags);
+    return fs->fd;
 }
 
-static DIR *local_opendir(FsContext *ctx, V9fsPath *fs_path)
+static int local_opendir(FsContext *ctx,
+                         V9fsPath *fs_path, V9fsFidOpenState *fs)
 {
     char buffer[PATH_MAX];
     char *path = fs_path->data;
 
-    return opendir(rpath(ctx, path, buffer));
+    fs->dir = opendir(rpath(ctx, path, buffer));
+    if (!fs->dir) {
+        return -1;
+    }
+    return 0;
 }
 
-static void local_rewinddir(FsContext *ctx, DIR *dir)
+static void local_rewinddir(FsContext *ctx, V9fsFidOpenState *fs)
 {
-    return rewinddir(dir);
+    return rewinddir(fs->dir);
 }
 
-static off_t local_telldir(FsContext *ctx, DIR *dir)
+static off_t local_telldir(FsContext *ctx, V9fsFidOpenState *fs)
 {
-    return telldir(dir);
+    return telldir(fs->dir);
 }
 
-static int local_readdir_r(FsContext *ctx, DIR *dir, struct dirent *entry,
+static int local_readdir_r(FsContext *ctx, V9fsFidOpenState *fs,
+                           struct dirent *entry,
                            struct dirent **result)
 {
-    return readdir_r(dir, entry, result);
+    return readdir_r(fs->dir, entry, result);
 }
 
-static void local_seekdir(FsContext *ctx, DIR *dir, off_t off)
+static void local_seekdir(FsContext *ctx, V9fsFidOpenState *fs, off_t off)
 {
-    return seekdir(dir, off);
+    return seekdir(fs->dir, off);
 }
 
-static ssize_t local_preadv(FsContext *ctx, int fd, const struct iovec *iov,
+static ssize_t local_preadv(FsContext *ctx, V9fsFidOpenState *fs,
+                            const struct iovec *iov,
                             int iovcnt, off_t offset)
 {
 #ifdef CONFIG_PREADV
-    return preadv(fd, iov, iovcnt, offset);
+    return preadv(fs->fd, iov, iovcnt, offset);
 #else
-    int err = lseek(fd, offset, SEEK_SET);
+    int err = lseek(fs->fd, offset, SEEK_SET);
     if (err == -1) {
         return err;
     } else {
-        return readv(fd, iov, iovcnt);
+        return readv(fs->fd, iov, iovcnt);
     }
 #endif
 }
 
-static ssize_t local_pwritev(FsContext *ctx, int fd, const struct iovec *iov,
+static ssize_t local_pwritev(FsContext *ctx, V9fsFidOpenState *fs,
+                             const struct iovec *iov,
                              int iovcnt, off_t offset)
 {
     ssize_t ret
 ;
 #ifdef CONFIG_PREADV
-    ret = pwritev(fd, iov, iovcnt, offset);
+    ret = pwritev(fs->fd, iov, iovcnt, offset);
 #else
-    int err = lseek(fd, offset, SEEK_SET);
+    int err = lseek(fs->fd, offset, SEEK_SET);
     if (err == -1) {
         return err;
     } else {
-        ret = writev(fd, iov, iovcnt);
+        ret = writev(fs->fd, iov, iovcnt);
     }
 #endif
 #ifdef CONFIG_SYNC_FILE_RANGE
@@ -240,7 +250,7 @@ static ssize_t local_pwritev(FsContext *ctx, int fd, const struct iovec *iov,
          * We want to ensure that we don't leave dirty pages in the cache
          * after write when writeout=immediate is sepcified.
          */
-        sync_file_range(fd, offset, ret,
+        sync_file_range(fs->fd, offset, ret,
                         SYNC_FILE_RANGE_WAIT_BEFORE | SYNC_FILE_RANGE_WRITE);
     }
 #endif
@@ -281,7 +291,7 @@ static int local_mknod(FsContext *fs_ctx, V9fsPath *dir_path,
         if (err == -1) {
             goto out;
         }
-        local_set_xattr(rpath(fs_ctx, path, buffer), credp);
+        err = local_set_xattr(rpath(fs_ctx, path, buffer), credp);
         if (err == -1) {
             serrno = errno;
             goto err_end;
@@ -356,10 +366,11 @@ out:
     return err;
 }
 
-static int local_fstat(FsContext *fs_ctx, int fd, struct stat *stbuf)
+static int local_fstat(FsContext *fs_ctx,
+                       V9fsFidOpenState *fs, struct stat *stbuf)
 {
     int err;
-    err = fstat(fd, stbuf);
+    err = fstat(fs->fd, stbuf);
     if (err) {
         return err;
     }
@@ -370,16 +381,20 @@ static int local_fstat(FsContext *fs_ctx, int fd, struct stat *stbuf)
         mode_t tmp_mode;
         dev_t tmp_dev;
 
-        if (fgetxattr(fd, "user.virtfs.uid", &tmp_uid, sizeof(uid_t)) > 0) {
+        if (fgetxattr(fs->fd, "user.virtfs.uid",
+                      &tmp_uid, sizeof(uid_t)) > 0) {
             stbuf->st_uid = tmp_uid;
         }
-        if (fgetxattr(fd, "user.virtfs.gid", &tmp_gid, sizeof(gid_t)) > 0) {
+        if (fgetxattr(fs->fd, "user.virtfs.gid",
+                      &tmp_gid, sizeof(gid_t)) > 0) {
             stbuf->st_gid = tmp_gid;
         }
-        if (fgetxattr(fd, "user.virtfs.mode", &tmp_mode, sizeof(mode_t)) > 0) {
+        if (fgetxattr(fs->fd, "user.virtfs.mode",
+                      &tmp_mode, sizeof(mode_t)) > 0) {
             stbuf->st_mode = tmp_mode;
         }
-        if (fgetxattr(fd, "user.virtfs.rdev", &tmp_dev, sizeof(dev_t)) > 0) {
+        if (fgetxattr(fs->fd, "user.virtfs.rdev",
+                      &tmp_dev, sizeof(dev_t)) > 0) {
                 stbuf->st_rdev = tmp_dev;
         }
     }
@@ -387,7 +402,7 @@ static int local_fstat(FsContext *fs_ctx, int fd, struct stat *stbuf)
 }
 
 static int local_open2(FsContext *fs_ctx, V9fsPath *dir_path, const char *name,
-                       int flags, FsCred *credp)
+                       int flags, FsCred *credp, V9fsFidOpenState *fs)
 {
     char *path;
     int fd = -1;
@@ -428,6 +443,7 @@ static int local_open2(FsContext *fs_ctx, V9fsPath *dir_path, const char *name,
         }
     }
     err = fd;
+    fs->fd = fd;
     goto out;
 
 err_end:
@@ -551,15 +567,12 @@ static int local_chown(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp)
     char *path = fs_path->data;
 
     if ((credp->fc_uid == -1 && credp->fc_gid == -1) ||
-            (fs_ctx->export_flags & V9FS_SM_PASSTHROUGH)) {
-        return lchown(rpath(fs_ctx, path, buffer), credp->fc_uid,
-                credp->fc_gid);
+        (fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
+        (fs_ctx->export_flags & V9FS_SM_NONE)) {
+        return lchown(rpath(fs_ctx, path, buffer),
+                      credp->fc_uid, credp->fc_gid);
     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
         return local_set_xattr(rpath(fs_ctx, path, buffer), credp);
-    } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
-               (fs_ctx->export_flags & V9FS_SM_NONE)) {
-        return lchown(rpath(fs_ctx, path, buffer), credp->fc_uid,
-                credp->fc_gid);
     }
     return -1;
 }
@@ -580,12 +593,12 @@ static int local_remove(FsContext *ctx, const char *path)
     return remove(rpath(ctx, path, buffer));
 }
 
-static int local_fsync(FsContext *ctx, int fd, int datasync)
+static int local_fsync(FsContext *ctx, V9fsFidOpenState *fs, int datasync)
 {
     if (datasync) {
-        return qemu_fdatasync(fd);
+        return qemu_fdatasync(fs->fd);
     } else {
-        return fsync(fd);
+        return fsync(fs->fd);
     }
 }
 
@@ -680,7 +693,9 @@ static int local_unlinkat(FsContext *ctx, V9fsPath *dir,
 static int local_ioc_getversion(FsContext *ctx, V9fsPath *path,
                                 mode_t st_mode, uint64_t *st_gen)
 {
-    int err, fd;
+    int err;
+    V9fsFidOpenState fid_open;
+
     /*
      * Do not try to open special files like device nodes, fifos etc
      * We can get fd for regular files and directories only
@@ -688,12 +703,12 @@ static int local_ioc_getversion(FsContext *ctx, V9fsPath *path,
     if (!S_ISREG(st_mode) && !S_ISDIR(st_mode)) {
             return 0;
     }
-    fd = local_open(ctx, path, O_RDONLY);
-    if (fd < 0) {
-        return fd;
+    err = local_open(ctx, path, O_RDONLY, &fid_open);
+    if (err < 0) {
+        return err;
     }
-    err = ioctl(fd, FS_IOC_GETVERSION, st_gen);
-    local_close(ctx, fd);
+    err = ioctl(fid_open.fd, FS_IOC_GETVERSION, st_gen);
+    local_close(ctx, &fid_open);
     return err;
 }
 
diff --git a/hw/9pfs/virtio-9p-synth.c b/hw/9pfs/virtio-9p-synth.c
new file mode 100644
index 0000000..f573616
--- /dev/null
+++ b/hw/9pfs/virtio-9p-synth.c
@@ -0,0 +1,571 @@
+/*
+ * Virtio 9p synthetic file system support
+ *
+ * Copyright IBM, Corp. 2011
+ *
+ * Authors:
+ *  Malahal Naineni <malahal@us.ibm.com>
+ *  Aneesh Kumar K.V <aneesh.kumar@linux.vnet.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 "hw/virtio.h"
+#include "virtio-9p.h"
+#include "virtio-9p-xattr.h"
+#include "fsdev/qemu-fsdev.h"
+#include "virtio-9p-synth.h"
+
+#include <sys/stat.h>
+
+/* Root node for synth file system */
+V9fsSynthNode v9fs_synth_root = {
+    .name = "/",
+    .actual_attr = {
+        .mode = 0555 | S_IFDIR,
+        .nlink = 1,
+    },
+    .attr = &v9fs_synth_root.actual_attr,
+};
+
+static QemuMutex  v9fs_synth_mutex;
+static int v9fs_synth_node_count;
+/* set to 1 when the synth fs is ready */
+static int v9fs_synth_fs;
+
+static V9fsSynthNode *v9fs_add_dir_node(V9fsSynthNode *parent, int mode,
+                                        const char *name,
+                                        V9fsSynthNodeAttr *attr, int inode)
+{
+    V9fsSynthNode *node;
+
+    /* Add directory type and remove write bits */
+    mode = ((mode & 0777) | S_IFDIR) & ~(S_IWUSR | S_IWGRP | S_IWOTH);
+    node = g_malloc0(sizeof(V9fsSynthNode));
+    if (attr) {
+        /* We are adding .. or . entries */
+        node->attr = attr;
+        node->attr->nlink++;
+    } else {
+        node->attr = &node->actual_attr;
+        node->attr->inode = inode;
+        node->attr->nlink = 1;
+        /* We don't allow write to directories */
+        node->attr->mode   = mode;
+        node->attr->write = NULL;
+        node->attr->read  = NULL;
+    }
+    node->private = node;
+    strncpy(node->name, name, sizeof(node->name));
+    QLIST_INSERT_HEAD_RCU(&parent->child, node, sibling);
+    return node;
+}
+
+int qemu_v9fs_synth_mkdir(V9fsSynthNode *parent, int mode,
+                          const char *name, V9fsSynthNode **result)
+{
+    int ret;
+    V9fsSynthNode *node, *tmp;
+
+    if (!v9fs_synth_fs) {
+        return EAGAIN;
+    }
+    if (!name || (strlen(name) >= NAME_MAX)) {
+        return EINVAL;
+    }
+    if (!parent) {
+        parent = &v9fs_synth_root;
+    }
+    qemu_mutex_lock(&v9fs_synth_mutex);
+    QLIST_FOREACH(tmp, &parent->child, sibling) {
+        if (!strcmp(tmp->name, name)) {
+            ret = EEXIST;
+            goto err_out;
+        }
+    }
+    /* Add the name */
+    node = v9fs_add_dir_node(parent, mode, name, NULL, v9fs_synth_node_count++);
+    v9fs_add_dir_node(node, parent->attr->mode, "..",
+                      parent->attr, parent->attr->inode);
+    v9fs_add_dir_node(node, node->attr->mode, ".",
+                      node->attr, node->attr->inode);
+    *result = node;
+    ret = 0;
+err_out:
+    qemu_mutex_unlock(&v9fs_synth_mutex);
+    return ret;
+}
+
+int qemu_v9fs_synth_add_file(V9fsSynthNode *parent, int mode,
+                             const char *name, v9fs_synth_read read,
+                             v9fs_synth_write write, void *arg)
+{
+    int ret;
+    V9fsSynthNode *node, *tmp;
+
+    if (!v9fs_synth_fs) {
+        return EAGAIN;
+    }
+    if (!name || (strlen(name) >= NAME_MAX)) {
+        return EINVAL;
+    }
+    if (!parent) {
+        parent = &v9fs_synth_root;
+    }
+
+    qemu_mutex_lock(&v9fs_synth_mutex);
+    QLIST_FOREACH(tmp, &parent->child, sibling) {
+        if (!strcmp(tmp->name, name)) {
+            ret = EEXIST;
+            goto err_out;
+        }
+    }
+    /* Add file type and remove write bits */
+    mode = ((mode & 0777) | S_IFREG);
+    node = g_malloc0(sizeof(V9fsSynthNode));
+    node->attr         = &node->actual_attr;
+    node->attr->inode  = v9fs_synth_node_count++;
+    node->attr->nlink  = 1;
+    node->attr->read   = read;
+    node->attr->write  = write;
+    node->attr->mode   = mode;
+    node->private      = arg;
+    strncpy(node->name, name, sizeof(node->name));
+    QLIST_INSERT_HEAD_RCU(&parent->child, node, sibling);
+    ret = 0;
+err_out:
+    qemu_mutex_unlock(&v9fs_synth_mutex);
+    return ret;
+}
+
+static void v9fs_synth_fill_statbuf(V9fsSynthNode *node, struct stat *stbuf)
+{
+    stbuf->st_dev = 0;
+    stbuf->st_ino = node->attr->inode;
+    stbuf->st_mode = node->attr->mode;
+    stbuf->st_nlink = node->attr->nlink;
+    stbuf->st_uid = 0;
+    stbuf->st_gid = 0;
+    stbuf->st_rdev = 0;
+    stbuf->st_size = 0;
+    stbuf->st_blksize = 0;
+    stbuf->st_blocks = 0;
+    stbuf->st_atime = 0;
+    stbuf->st_mtime = 0;
+    stbuf->st_ctime = 0;
+}
+
+static int v9fs_synth_lstat(FsContext *fs_ctx,
+                            V9fsPath *fs_path, struct stat *stbuf)
+{
+    V9fsSynthNode *node = *(V9fsSynthNode **)fs_path->data;
+
+    v9fs_synth_fill_statbuf(node, stbuf);
+    return 0;
+}
+
+static int v9fs_synth_fstat(FsContext *fs_ctx,
+                            V9fsFidOpenState *fs, struct stat *stbuf)
+{
+    V9fsSynthOpenState *synth_open = fs->private;
+    v9fs_synth_fill_statbuf(synth_open->node, stbuf);
+    return 0;
+}
+
+static int v9fs_synth_opendir(FsContext *ctx,
+                             V9fsPath *fs_path, V9fsFidOpenState *fs)
+{
+    V9fsSynthOpenState *synth_open;
+    V9fsSynthNode *node = *(V9fsSynthNode **)fs_path->data;
+
+    synth_open = g_malloc(sizeof(*synth_open));
+    synth_open->node = node;
+    node->open_count++;
+    fs->private = synth_open;
+    return 0;
+}
+
+static int v9fs_synth_closedir(FsContext *ctx, V9fsFidOpenState *fs)
+{
+    V9fsSynthOpenState *synth_open = fs->private;
+    V9fsSynthNode *node = synth_open->node;
+
+    node->open_count--;
+    g_free(synth_open);
+    fs->private = NULL;
+    return 0;
+}
+
+static off_t v9fs_synth_telldir(FsContext *ctx, V9fsFidOpenState *fs)
+{
+    V9fsSynthOpenState *synth_open = fs->private;
+    return synth_open->offset;
+}
+
+static void v9fs_synth_seekdir(FsContext *ctx, V9fsFidOpenState *fs, off_t off)
+{
+    V9fsSynthOpenState *synth_open = fs->private;
+    synth_open->offset = off;
+}
+
+static void v9fs_synth_rewinddir(FsContext *ctx, V9fsFidOpenState *fs)
+{
+    v9fs_synth_seekdir(ctx, fs, 0);
+}
+
+static void v9fs_synth_direntry(V9fsSynthNode *node,
+                                struct dirent *entry, off_t off)
+{
+    strcpy(entry->d_name, node->name);
+    entry->d_ino = node->attr->inode;
+    entry->d_off = off + 1;
+}
+
+static int v9fs_synth_get_dentry(V9fsSynthNode *dir, struct dirent *entry,
+                                 struct dirent **result, off_t off)
+{
+    int i = 0;
+    V9fsSynthNode *node;
+
+    rcu_read_lock();
+    QLIST_FOREACH(node, &dir->child, sibling) {
+        /* This is the off child of the directory */
+        if (i == off) {
+            break;
+        }
+        i++;
+    }
+    rcu_read_unlock();
+    if (!node) {
+        /* end of directory */
+        *result = NULL;
+        return 0;
+    }
+    v9fs_synth_direntry(node, entry, off);
+    *result = entry;
+    return 0;
+}
+
+static int v9fs_synth_readdir_r(FsContext *ctx, V9fsFidOpenState *fs,
+                                struct dirent *entry, struct dirent **result)
+{
+    int ret;
+    V9fsSynthOpenState *synth_open = fs->private;
+    V9fsSynthNode *node = synth_open->node;
+    ret = v9fs_synth_get_dentry(node, entry, result, synth_open->offset);
+    if (!ret && *result != NULL) {
+        synth_open->offset++;
+    }
+    return ret;
+}
+
+static int v9fs_synth_open(FsContext *ctx, V9fsPath *fs_path,
+                           int flags, V9fsFidOpenState *fs)
+{
+    V9fsSynthOpenState *synth_open;
+    V9fsSynthNode *node = *(V9fsSynthNode **)fs_path->data;
+
+    synth_open = g_malloc(sizeof(*synth_open));
+    synth_open->node = node;
+    node->open_count++;
+    fs->private = synth_open;
+    return 0;
+}
+
+static int v9fs_synth_open2(FsContext *fs_ctx, V9fsPath *dir_path,
+                            const char *name, int flags,
+                            FsCred *credp, V9fsFidOpenState *fs)
+{
+    errno = ENOSYS;
+    return -1;
+}
+
+static int v9fs_synth_close(FsContext *ctx, V9fsFidOpenState *fs)
+{
+    V9fsSynthOpenState *synth_open = fs->private;
+    V9fsSynthNode *node = synth_open->node;
+
+    node->open_count--;
+    g_free(synth_open);
+    fs->private = NULL;
+    return 0;
+}
+
+static ssize_t v9fs_synth_pwritev(FsContext *ctx, V9fsFidOpenState *fs,
+                                  const struct iovec *iov,
+                                  int iovcnt, off_t offset)
+{
+    int i, count = 0, wcount;
+    V9fsSynthOpenState *synth_open = fs->private;
+    V9fsSynthNode *node = synth_open->node;
+    if (!node->attr->write) {
+        errno = EPERM;
+        return -1;
+    }
+    for (i = 0; i < iovcnt; i++) {
+        wcount = node->attr->write(iov[i].iov_base, iov[i].iov_len,
+                                   offset, node->private);
+        offset += wcount;
+        count  += wcount;
+        /* If we wrote less than requested. we are done */
+        if (wcount < iov[i].iov_len) {
+            break;
+        }
+    }
+    return count;
+}
+
+static ssize_t v9fs_synth_preadv(FsContext *ctx, V9fsFidOpenState *fs,
+                                 const struct iovec *iov,
+                                 int iovcnt, off_t offset)
+{
+    int i, count = 0, rcount;
+    V9fsSynthOpenState *synth_open = fs->private;
+    V9fsSynthNode *node = synth_open->node;
+    if (!node->attr->read) {
+        errno = EPERM;
+        return -1;
+    }
+    for (i = 0; i < iovcnt; i++) {
+        rcount = node->attr->read(iov[i].iov_base, iov[i].iov_len,
+                                  offset, node->private);
+        offset += rcount;
+        count  += rcount;
+        /* If we read less than requested. we are done */
+        if (rcount < iov[i].iov_len) {
+            break;
+        }
+    }
+    return count;
+}
+
+static int v9fs_synth_truncate(FsContext *ctx, V9fsPath *path, off_t offset)
+{
+    errno = ENOSYS;
+    return -1;
+}
+
+static int v9fs_synth_chmod(FsContext *fs_ctx, V9fsPath *path, FsCred *credp)
+{
+    errno = EPERM;
+    return -1;
+}
+
+static int v9fs_synth_mknod(FsContext *fs_ctx, V9fsPath *path,
+                       const char *buf, FsCred *credp)
+{
+    errno = EPERM;
+    return -1;
+}
+
+static int v9fs_synth_mkdir(FsContext *fs_ctx, V9fsPath *path,
+                       const char *buf, FsCred *credp)
+{
+    errno = EPERM;
+    return -1;
+}
+
+static ssize_t v9fs_synth_readlink(FsContext *fs_ctx, V9fsPath *path,
+                                   char *buf, size_t bufsz)
+{
+    errno = ENOSYS;
+    return -1;
+}
+
+static int v9fs_synth_symlink(FsContext *fs_ctx, const char *oldpath,
+                              V9fsPath *newpath, const char *buf, FsCred *credp)
+{
+    errno = EPERM;
+    return -1;
+}
+
+static int v9fs_synth_link(FsContext *fs_ctx, V9fsPath *oldpath,
+                           V9fsPath *newpath, const char *buf)
+{
+    errno = EPERM;
+    return -1;
+}
+
+static int v9fs_synth_rename(FsContext *ctx, const char *oldpath,
+                             const char *newpath)
+{
+    errno = EPERM;
+    return -1;
+}
+
+static int v9fs_synth_chown(FsContext *fs_ctx, V9fsPath *path, FsCred *credp)
+{
+    errno = EPERM;
+    return -1;
+}
+
+static int v9fs_synth_utimensat(FsContext *fs_ctx, V9fsPath *path,
+                                const struct timespec *buf)
+{
+    errno = EPERM;
+    return 0;
+}
+
+static int v9fs_synth_remove(FsContext *ctx, const char *path)
+{
+    errno = EPERM;
+    return -1;
+}
+
+static int v9fs_synth_fsync(FsContext *ctx, V9fsFidOpenState *fs, int datasync)
+{
+    errno = ENOSYS;
+    return 0;
+}
+
+static int v9fs_synth_statfs(FsContext *s, V9fsPath *fs_path,
+                             struct statfs *stbuf)
+{
+    stbuf->f_type = 0xABCD;
+    stbuf->f_bsize = 512;
+    stbuf->f_blocks = 0;
+    stbuf->f_files = v9fs_synth_node_count;
+    stbuf->f_namelen = NAME_MAX;
+    return 0;
+}
+
+static ssize_t v9fs_synth_lgetxattr(FsContext *ctx, V9fsPath *path,
+                                    const char *name, void *value, size_t size)
+{
+    errno = ENOTSUP;
+    return -1;
+}
+
+static ssize_t v9fs_synth_llistxattr(FsContext *ctx, V9fsPath *path,
+                                     void *value, size_t size)
+{
+    errno = ENOTSUP;
+    return -1;
+}
+
+static int v9fs_synth_lsetxattr(FsContext *ctx, V9fsPath *path,
+                                const char *name, void *value,
+                                size_t size, int flags)
+{
+    errno = ENOTSUP;
+    return -1;
+}
+
+static int v9fs_synth_lremovexattr(FsContext *ctx,
+                                   V9fsPath *path, const char *name)
+{
+    errno = ENOTSUP;
+    return -1;
+}
+
+static int v9fs_synth_name_to_path(FsContext *ctx, V9fsPath *dir_path,
+                                   const char *name, V9fsPath *target)
+{
+    V9fsSynthNode *node;
+    V9fsSynthNode *dir_node;
+
+    /* "." and ".." are not allowed */
+    if (!strcmp(name, ".") || !strcmp(name, "..")) {
+        errno = EINVAL;
+        return -1;
+
+    }
+    if (!dir_path) {
+        dir_node = &v9fs_synth_root;
+    } else {
+        dir_node = *(V9fsSynthNode **)dir_path->data;
+    }
+    if (!strcmp(name, "/")) {
+        node = dir_node;
+        goto out;
+    }
+    /* search for the name in the childern */
+    rcu_read_lock();
+    QLIST_FOREACH(node, &dir_node->child, sibling) {
+        if (!strcmp(node->name, name)) {
+            break;
+        }
+    }
+    rcu_read_unlock();
+
+    if (!node) {
+        errno = ENOENT;
+        return -1;
+    }
+out:
+    /* Copy the node pointer to fid */
+    target->data = g_malloc(sizeof(void *));
+    memcpy(target->data, &node, sizeof(void *));
+    target->size = sizeof(void *);
+    return 0;
+}
+
+static int v9fs_synth_renameat(FsContext *ctx, V9fsPath *olddir,
+                               const char *old_name, V9fsPath *newdir,
+                               const char *new_name)
+{
+    errno = EPERM;
+    return -1;
+}
+
+static int v9fs_synth_unlinkat(FsContext *ctx, V9fsPath *dir,
+                               const char *name, int flags)
+{
+    errno = EPERM;
+    return -1;
+}
+
+static int v9fs_synth_init(FsContext *ctx)
+{
+    QLIST_INIT(&v9fs_synth_root.child);
+    qemu_mutex_init(&v9fs_synth_mutex);
+
+    /* Add "." and ".." entries for root */
+    v9fs_add_dir_node(&v9fs_synth_root, v9fs_synth_root.attr->mode,
+                      "..", v9fs_synth_root.attr, v9fs_synth_root.attr->inode);
+    v9fs_add_dir_node(&v9fs_synth_root, v9fs_synth_root.attr->mode,
+                      ".", v9fs_synth_root.attr, v9fs_synth_root.attr->inode);
+
+    /* Mark the subsystem is ready for use */
+    v9fs_synth_fs = 1;
+    return 0;
+}
+
+FileOperations synth_ops = {
+    .init         = v9fs_synth_init,
+    .lstat        = v9fs_synth_lstat,
+    .readlink     = v9fs_synth_readlink,
+    .close        = v9fs_synth_close,
+    .closedir     = v9fs_synth_closedir,
+    .open         = v9fs_synth_open,
+    .opendir      = v9fs_synth_opendir,
+    .rewinddir    = v9fs_synth_rewinddir,
+    .telldir      = v9fs_synth_telldir,
+    .readdir_r    = v9fs_synth_readdir_r,
+    .seekdir      = v9fs_synth_seekdir,
+    .preadv       = v9fs_synth_preadv,
+    .pwritev      = v9fs_synth_pwritev,
+    .chmod        = v9fs_synth_chmod,
+    .mknod        = v9fs_synth_mknod,
+    .mkdir        = v9fs_synth_mkdir,
+    .fstat        = v9fs_synth_fstat,
+    .open2        = v9fs_synth_open2,
+    .symlink      = v9fs_synth_symlink,
+    .link         = v9fs_synth_link,
+    .truncate     = v9fs_synth_truncate,
+    .rename       = v9fs_synth_rename,
+    .chown        = v9fs_synth_chown,
+    .utimensat    = v9fs_synth_utimensat,
+    .remove       = v9fs_synth_remove,
+    .fsync        = v9fs_synth_fsync,
+    .statfs       = v9fs_synth_statfs,
+    .lgetxattr    = v9fs_synth_lgetxattr,
+    .llistxattr   = v9fs_synth_llistxattr,
+    .lsetxattr    = v9fs_synth_lsetxattr,
+    .lremovexattr = v9fs_synth_lremovexattr,
+    .name_to_path = v9fs_synth_name_to_path,
+    .renameat     = v9fs_synth_renameat,
+    .unlinkat     = v9fs_synth_unlinkat,
+};
diff --git a/hw/9pfs/virtio-9p-synth.h b/hw/9pfs/virtio-9p-synth.h
new file mode 100644
index 0000000..e03f434
--- /dev/null
+++ b/hw/9pfs/virtio-9p-synth.h
@@ -0,0 +1,50 @@
+/*
+ * Virtio 9p
+ *
+ * Copyright IBM, Corp. 2011
+ *
+ * Authors:
+ *  Aneesh Kumar K.V <aneesh.kumar@linux.vnet.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 <unistd.h>
+#include <sys/types.h>
+#include <limits.h>
+
+typedef struct V9fsSynthNode V9fsSynthNode;
+typedef ssize_t (*v9fs_synth_read)(void *buf, int len, off_t offset,
+                                   void *arg);
+typedef ssize_t (*v9fs_synth_write)(void *buf, int len, off_t offset,
+                                    void *arg);
+typedef struct V9fsSynthNodeAttr {
+    int mode;
+    int inode;
+    int nlink;
+    v9fs_synth_read read;
+    v9fs_synth_write write;
+} V9fsSynthNodeAttr;
+
+struct V9fsSynthNode {
+    QLIST_HEAD(, V9fsSynthNode) child;
+    QLIST_ENTRY(V9fsSynthNode) sibling;
+    char name[NAME_MAX];
+    V9fsSynthNodeAttr *attr;
+    V9fsSynthNodeAttr actual_attr;
+    void *private;
+    int open_count;
+};
+
+typedef struct V9fsSynthOpenState {
+    off_t offset;
+    V9fsSynthNode *node;
+} V9fsSynthOpenState;
+
+extern int qemu_v9fs_synth_mkdir(V9fsSynthNode *parent, int mode,
+                                 const char *name, V9fsSynthNode **result);
+extern int qemu_v9fs_synth_add_file(V9fsSynthNode *parent, int mode,
+                                    const char *name, v9fs_synth_read read,
+                                    v9fs_synth_write write, void *arg);
diff --git a/hw/9pfs/virtio-9p.c b/hw/9pfs/virtio-9p.c
index 8b6813f..0777ece 100644
--- a/hw/9pfs/virtio-9p.c
+++ b/hw/9pfs/virtio-9p.c
@@ -455,11 +455,11 @@ static int free_fid(V9fsPDU *pdu, V9fsFidState *fidp)
     if (fidp->fid_type == P9_FID_FILE) {
         /* If we reclaimed the fd no need to close */
         if (fidp->fs.fd != -1) {
-            retval = v9fs_co_close(pdu, fidp->fs.fd);
+            retval = v9fs_co_close(pdu, &fidp->fs);
         }
     } else if (fidp->fid_type == P9_FID_DIR) {
         if (fidp->fs.dir != NULL) {
-            retval = v9fs_co_closedir(pdu, fidp->fs.dir);
+            retval = v9fs_co_closedir(pdu, &fidp->fs);
         }
     } else if (fidp->fid_type == P9_FID_XATTR) {
         retval = v9fs_xattr_fid_clunk(pdu, fidp);
@@ -567,9 +567,9 @@ void v9fs_reclaim_fd(V9fsPDU *pdu)
         f = reclaim_list;
         reclaim_list = f->rclm_lst;
         if (f->fid_type == P9_FID_FILE) {
-            v9fs_co_close(pdu, f->fs_reclaim.fd);
+            v9fs_co_close(pdu, &f->fs_reclaim);
         } else if (f->fid_type == P9_FID_DIR) {
-            v9fs_co_closedir(pdu, f->fs_reclaim.dir);
+            v9fs_co_closedir(pdu, &f->fs_reclaim);
         }
         f->rclm_lst = NULL;
         /*
@@ -1271,6 +1271,11 @@ static void v9fs_fix_path(V9fsPath *dst, V9fsPath *src, int len)
     dst->size++;
 }
 
+static inline bool is_ro_export(FsContext *ctx)
+{
+    return ctx->export_flags & V9FS_RDONLY;
+}
+
 static void v9fs_version(void *opaque)
 {
     V9fsPDU *pdu = opaque;
@@ -1690,6 +1695,14 @@ static void v9fs_open(void *opaque)
         } else {
             flags = omode_to_uflags(mode);
         }
+        if (is_ro_export(&s->ctx)) {
+            if (mode & O_WRONLY || mode & O_RDWR ||
+                mode & O_APPEND || mode & O_TRUNC) {
+                err = -EROFS;
+                goto out;
+            }
+            flags |= O_NOATIME;
+        }
         err = v9fs_co_open(pdu, fidp, flags);
         if (err < 0) {
             goto out;
@@ -2996,7 +3009,7 @@ static void v9fs_lock(void *opaque)
         err = -ENOENT;
         goto out_nofid;
     }
-    err = v9fs_co_fstat(pdu, fidp->fs.fd, &stbuf);
+    err = v9fs_co_fstat(pdu, fidp, &stbuf);
     if (err < 0) {
         goto out;
     }
@@ -3039,7 +3052,7 @@ static void v9fs_getlock(void *opaque)
         err = -ENOENT;
         goto out_nofid;
     }
-    err = v9fs_co_fstat(pdu, fidp->fs.fd, &stbuf);
+    err = v9fs_co_fstat(pdu, fidp, &stbuf);
     if (err < 0) {
         goto out;
     }
@@ -3309,6 +3322,39 @@ static void v9fs_op_not_supp(void *opaque)
     complete_pdu(pdu->s, pdu, -EOPNOTSUPP);
 }
 
+static void v9fs_fs_ro(void *opaque)
+{
+    V9fsPDU *pdu = opaque;
+    complete_pdu(pdu->s, pdu, -EROFS);
+}
+
+static inline bool is_read_only_op(V9fsPDU *pdu)
+{
+    switch (pdu->id) {
+    case P9_TREADDIR:
+    case P9_TSTATFS:
+    case P9_TGETATTR:
+    case P9_TXATTRWALK:
+    case P9_TLOCK:
+    case P9_TGETLOCK:
+    case P9_TREADLINK:
+    case P9_TVERSION:
+    case P9_TLOPEN:
+    case P9_TATTACH:
+    case P9_TSTAT:
+    case P9_TWALK:
+    case P9_TCLUNK:
+    case P9_TFSYNC:
+    case P9_TOPEN:
+    case P9_TREAD:
+    case P9_TAUTH:
+    case P9_TFLUSH:
+        return 1;
+    default:
+        return 0;
+    }
+}
+
 static void submit_pdu(V9fsState *s, V9fsPDU *pdu)
 {
     Coroutine *co;
@@ -3320,6 +3366,10 @@ static void submit_pdu(V9fsState *s, V9fsPDU *pdu)
     } else {
         handler = pdu_co_handlers[pdu->id];
     }
+
+    if (is_ro_export(&s->ctx) && !is_read_only_op(pdu)) {
+        handler = v9fs_fs_ro;
+    }
     co = qemu_coroutine_create(handler);
     qemu_coroutine_enter(co, pdu);
 }
diff --git a/hw/9pfs/virtio-9p.h b/hw/9pfs/virtio-9p.h
index 802f580..7f88356 100644
--- a/hw/9pfs/virtio-9p.h
+++ b/hw/9pfs/virtio-9p.h
@@ -204,20 +204,29 @@ typedef struct V9fsXattr
     int flags;
 } V9fsXattr;
 
+/*
+ * Filled by fs driver on open and other
+ * calls.
+ */
+union V9fsFidOpenState {
+    int fd;
+    DIR *dir;
+    V9fsXattr xattr;
+    /*
+     * private pointer for fs drivers, that
+     * have its own internal representation of
+     * open files.
+     */
+    void *private;
+};
+
 struct V9fsFidState
 {
     int fid_type;
     int32_t fid;
     V9fsPath path;
-    union {
-        int fd;
-        DIR *dir;
-        V9fsXattr xattr;
-    } fs;
-    union {
-        int fd;
-        DIR *dir;
-    } fs_reclaim;
+    V9fsFidOpenState fs;
+    V9fsFidOpenState fs_reclaim;
     int flags;
     int open_flags;
     uid_t uid;