diff --git a/Documentation/ABI/testing/sysfs-fs-virtiofs b/Documentation/ABI/testing/sysfs-fs-virtiofs
new file mode 100644
index 0000000000000000000000000000000000000000..4839dbce997e4224affbd5dfcc5d22ec79d49d86
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-fs-virtiofs
@@ -0,0 +1,11 @@
+What: /sys/fs/virtiofs/<n>/tag
+Date: Feb 2024
+Contact: virtio-fs@lists.linux.dev
+Description:
+ [RO] The mount "tag" that can be used to mount this filesystem.
+
+What: /sys/fs/virtiofs/<n>/device
+Date: Feb 2024
+Contact: virtio-fs@lists.linux.dev
+Description:
+ Symlink to the virtio device that exports this filesystem.
diff --git a/fs/fuse/virtio_fs.c b/fs/fuse/virtio_fs.c
index d84dacbdce2c9de254e286685e9746679537bbff..99b6113bbd138305968a37814a145bab2d120e6b 100644
--- a/fs/fuse/virtio_fs.c
+++ b/fs/fuse/virtio_fs.c
@@ -31,6 +31,9 @@
static DEFINE_MUTEX(virtio_fs_mutex);
static LIST_HEAD(virtio_fs_instances);
+/* The /sys/fs/virtio_fs/ kset */
+static struct kset *virtio_fs_kset;
+
enum {
VQ_HIPRIO,
VQ_REQUEST
@@ -55,7 +58,7 @@ struct virtio_fs_vq {
/* A virtio-fs device instance */
struct virtio_fs {
- struct kref refcount;
+ struct kobject kobj;
struct list_head list; /* on virtio_fs_instances */
char *tag;
struct virtio_fs_vq *vqs;
@@ -161,18 +164,40 @@ static inline void dec_in_flight_req(struct virtio_fs_vq *fsvq)
complete(&fsvq->in_flight_zero);
}
-static void release_virtio_fs_obj(struct kref *ref)
+static ssize_t tag_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ struct virtio_fs *fs = container_of(kobj, struct virtio_fs, kobj);
+
+ return sysfs_emit(buf, fs->tag);
+}
+
+static struct kobj_attribute virtio_fs_tag_attr = __ATTR_RO(tag);
+
+static struct attribute *virtio_fs_attrs[] = {
+ &virtio_fs_tag_attr.attr,
+ NULL
+};
+ATTRIBUTE_GROUPS(virtio_fs);
+
+static void virtio_fs_ktype_release(struct kobject *kobj)
{
- struct virtio_fs *vfs = container_of(ref, struct virtio_fs, refcount);
+ struct virtio_fs *vfs = container_of(kobj, struct virtio_fs, kobj);
kfree(vfs->vqs);
kfree(vfs);
}
+static const struct kobj_type virtio_fs_ktype = {
+ .release = virtio_fs_ktype_release,
+ .sysfs_ops = &kobj_sysfs_ops,
+ .default_groups = virtio_fs_groups,
+};
+
/* Make sure virtiofs_mutex is held */
static void virtio_fs_put(struct virtio_fs *fs)
{
- kref_put(&fs->refcount, release_virtio_fs_obj);
+ kobject_put(&fs->kobj);
}
static void virtio_fs_fiq_release(struct fuse_iqueue *fiq)
@@ -243,25 +268,44 @@ static void virtio_fs_start_all_queues(struct virtio_fs *fs)
}
/* Add a new instance to the list or return -EEXIST if tag name exists*/
-static int virtio_fs_add_instance(struct virtio_fs *fs)
+static int virtio_fs_add_instance(struct virtio_device *vdev,
+ struct virtio_fs *fs)
{
struct virtio_fs *fs2;
- bool duplicate = false;
+ int ret;
mutex_lock(&virtio_fs_mutex);
list_for_each_entry(fs2, &virtio_fs_instances, list) {
- if (strcmp(fs->tag, fs2->tag) == 0)
- duplicate = true;
+ if (strcmp(fs->tag, fs2->tag) == 0) {
+ mutex_unlock(&virtio_fs_mutex);
+ return -EEXIST;
+ }
+ }
+
+ /* Use the virtio_device's index as a unique identifier, there is no
+ * need to allocate our own identifiers because the virtio_fs instance
+ * is only visible to userspace as long as the underlying virtio_device
+ * exists.
+ */
+ fs->kobj.kset = virtio_fs_kset;
+ ret = kobject_add(&fs->kobj, NULL, "%d", vdev->index);
+ if (ret < 0) {
+ mutex_unlock(&virtio_fs_mutex);
+ return ret;
+ }
+
+ ret = sysfs_create_link(&fs->kobj, &vdev->dev.kobj, "device");
+ if (ret < 0) {
+ kobject_del(&fs->kobj);
+ mutex_unlock(&virtio_fs_mutex);
+ return ret;
}
- if (!duplicate)
- list_add_tail(&fs->list, &virtio_fs_instances);
+ list_add_tail(&fs->list, &virtio_fs_instances);
mutex_unlock(&virtio_fs_mutex);
- if (duplicate)
- return -EEXIST;
return 0;
}
@@ -274,7 +318,7 @@ static struct virtio_fs *virtio_fs_find_instance(const char *tag)
list_for_each_entry(fs, &virtio_fs_instances, list) {
if (strcmp(fs->tag, tag) == 0) {
- kref_get(&fs->refcount);
+ kobject_get(&fs->kobj);
goto found;
}
}
@@ -875,7 +919,7 @@ static int virtio_fs_probe(struct virtio_device *vdev)
fs = kzalloc(sizeof(*fs), GFP_KERNEL);
if (!fs)
return -ENOMEM;
- kref_init(&fs->refcount);
+ kobject_init(&fs->kobj, &virtio_fs_ktype);
vdev->priv = fs;
ret = virtio_fs_read_tag(vdev, fs);
@@ -897,7 +941,7 @@ static int virtio_fs_probe(struct virtio_device *vdev)
*/
virtio_device_ready(vdev);
- ret = virtio_fs_add_instance(fs);
+ ret = virtio_fs_add_instance(vdev, fs);
if (ret < 0)
goto out_vqs;
@@ -906,11 +950,10 @@ static int virtio_fs_probe(struct virtio_device *vdev)
out_vqs:
virtio_reset_device(vdev);
virtio_fs_cleanup_vqs(vdev);
- kfree(fs->vqs);
out:
vdev->priv = NULL;
- kfree(fs);
+ kobject_put(&fs->kobj);
return ret;
}
@@ -934,6 +977,8 @@ static void virtio_fs_remove(struct virtio_device *vdev)
mutex_lock(&virtio_fs_mutex);
/* This device is going away. No one should get new reference */
list_del_init(&fs->list);
+ sysfs_remove_link(&fs->kobj, "device");
+ kobject_del(&fs->kobj);
virtio_fs_stop_all_queues(fs);
virtio_fs_drain_all_queues_locked(fs);
virtio_reset_device(vdev);
@@ -1520,21 +1565,43 @@ static struct file_system_type virtio_fs_type = {
.kill_sb = virtio_kill_sb,
};
+static int __init virtio_fs_sysfs_init(void)
+{
+ virtio_fs_kset = kset_create_and_add("virtiofs", NULL, fs_kobj);
+ if (!virtio_fs_kset)
+ return -ENOMEM;
+ return 0;
+}
+
+static void __exit virtio_fs_sysfs_exit(void)
+{
+ kset_unregister(virtio_fs_kset);
+ virtio_fs_kset = NULL;
+}
+
static int __init virtio_fs_init(void)
{
int ret;
- ret = register_virtio_driver(&virtio_fs_driver);
+ ret = virtio_fs_sysfs_init();
if (ret < 0)
return ret;
+ ret = register_virtio_driver(&virtio_fs_driver);
+ if (ret < 0)
+ goto sysfs_exit;
+
ret = register_filesystem(&virtio_fs_type);
- if (ret < 0) {
- unregister_virtio_driver(&virtio_fs_driver);
- return ret;
- }
+ if (ret < 0)
+ goto unregister_virtio_driver;
return 0;
+
+unregister_virtio_driver:
+ unregister_virtio_driver(&virtio_fs_driver);
+sysfs_exit:
+ virtio_fs_sysfs_exit();
+ return ret;
}
module_init(virtio_fs_init);
@@ -1542,6 +1609,7 @@ static void __exit virtio_fs_exit(void)
{
unregister_filesystem(&virtio_fs_type);
unregister_virtio_driver(&virtio_fs_driver);
+ virtio_fs_sysfs_exit();
}
module_exit(virtio_fs_exit);