hw/9pfs: Add init callback to fs driver

This call back can be used to do fs driver specific initialization.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

fsdev/file-op-9p.h

@@ -19,6 +19,7 @@
 #include <sys/stat.h>
 #include <sys/uio.h>
 #include <sys/vfs.h>
+
 #define SM_LOCAL_MODE_BITS    0600
 #define SM_LOCAL_DIR_MODE_BITS    0700
 
@@ -66,6 +67,7 @@ void cred_init(FsCred *);
 
 typedef struct FileOperations
 {
+    int (*init)(struct FsContext *);
     int (*lstat)(FsContext *, V9fsPath *, struct stat *);
     ssize_t (*readlink)(FsContext *, V9fsPath *, char *, size_t);
     int (*chmod)(FsContext *, V9fsPath *, FsCred *);

hw/9pfs/virtio-9p-device.c

@@ -45,7 +45,7 @@ static void virtio_9p_get_config(VirtIODevice *vdev, uint8_t *config)
 }
 
 VirtIODevice *virtio_9p_init(DeviceState *dev, V9fsConf *conf)
- {
+{
     V9fsState *s;
     int i, len;
     struct stat stat;
@@ -133,6 +133,11 @@ VirtIODevice *virtio_9p_init(DeviceState *dev, V9fsConf *conf)
     s->fid_list = NULL;
     qemu_co_rwlock_init(&s->rename_lock);
 
+    if (s->ops->init(&s->ctx) < 0) {
+        fprintf(stderr, "Virtio-9p Failed to initialize fs-driver with id:%s"
+                " and export path:%s\n", conf->fsdev_id, s->ctx.fs_root);
+        exit(1);
+    }
     if (v9fs_init_worker_threads() < 0) {
         fprintf(stderr, "worker thread initialization failed\n");
         exit(1);

hw/9pfs/virtio-9p-local.c

@@ -21,7 +21,6 @@
 #include <sys/un.h>
 #include <attr/xattr.h>
 
-
 static int local_lstat(FsContext *fs_ctx, V9fsPath *fs_path, struct stat *stbuf)
 {
     int err;
@@ -646,7 +645,13 @@ static int local_unlinkat(FsContext *ctx, V9fsPath *dir,
     return ret;
 }
 
+static int local_init(FsContext *ctx)
+{
+    return 0;
+}
+
 FileOperations local_ops = {
+    .init  = local_init,
     .lstat = local_lstat,
     .readlink = local_readlink,
     .close = local_close,