virtiofs: simplify sb setup

Currently when acquiring an sb for virtiofs fuse_mount_get() is being
called from virtio_fs_set_super() if a new sb is being filled and
fuse_mount_put() is called unconditionally after sget_fc() returns.

The exact same result can be obtained by checking whether
fs_contex->s_fs_info was set to NULL (ref trasferred to sb->s_fs_info) and
only calling fuse_mount_put() if the ref wasn't transferred (error or
matching sb found).

This allows getting rid of virtio_fs_set_super() and fuse_mount_get().

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

3 files changed, 3 insertions, 26 deletions

diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index d51598017d13..c036c4dc714a 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -1025,11 +1025,6 @@ void fuse_conn_init(struct fuse_conn *fc, struct fuse_mount *fm,
 void fuse_conn_put(struct fuse_conn *fc);
 
 /**
- * Acquire reference to fuse_mount
- */
-struct fuse_mount *fuse_mount_get(struct fuse_mount *fm);
-
-/**
  * Release reference to fuse_mount
  */
 void fuse_mount_put(struct fuse_mount *fm);
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 1a47afc95f80..654708574d5e 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -742,13 +742,6 @@ void fuse_mount_put(struct fuse_mount *fm)
 }
 EXPORT_SYMBOL_GPL(fuse_mount_put);
 
-struct fuse_mount *fuse_mount_get(struct fuse_mount *fm)
-{
-	refcount_inc(&fm->count);
-	return fm;
-}
-EXPORT_SYMBOL_GPL(fuse_mount_get);
-
 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode)
 {
 	struct fuse_attr attr;
diff --git a/fs/fuse/virtio_fs.c b/fs/fuse/virtio_fs.c
index d2c0e58c6416..14d65db47778 100644
--- a/fs/fuse/virtio_fs.c
+++ b/fs/fuse/virtio_fs.c
@@ -1402,18 +1402,6 @@ static int virtio_fs_test_super(struct super_block *sb,
 	return fsc_fm->fc->iq.priv == sb_fm->fc->iq.priv;
 }
 
-static int virtio_fs_set_super(struct super_block *sb,
-			       struct fs_context *fsc)
-{
-	int err;
-
-	err = get_anon_bdev(&sb->s_dev);
-	if (!err)
-		fuse_mount_get(fsc->s_fs_info);
-
-	return err;
-}
-
 static int virtio_fs_get_tree(struct fs_context *fsc)
 {
 	struct virtio_fs *fs;
@@ -1456,8 +1444,9 @@ static int virtio_fs_get_tree(struct fs_context *fsc)
 	fc->auto_submounts = true;
 
 	fsc->s_fs_info = fm;
-	sb = sget_fc(fsc, virtio_fs_test_super, virtio_fs_set_super);
-	fuse_mount_put(fm);
+	sb = sget_fc(fsc, virtio_fs_test_super, set_anon_super_fc);
+	if (fsc->s_fs_info)
+		fuse_mount_put(fm);
 	if (IS_ERR(sb))
 		return PTR_ERR(sb);