From 3f9b9efd82a84f27e95d0414f852caf1fa839e83 Mon Sep 17 00:00:00 2001 From: Vivek Goyal Date: Tue, 9 Feb 2021 17:47:54 -0500 Subject: [PATCH] virtiofs: Fail dax mount if device does not support it Right now "mount -t virtiofs -o dax myfs /mnt/virtiofs" succeeds even if filesystem deivce does not have a cache window and hence DAX can't be supported. This gives a false sense to user that they are using DAX with virtiofs but fact of the matter is that they are not. Fix this by returning error if dax can't be supported and user has asked for it. Signed-off-by: Vivek Goyal Reviewed-by: Stefan Hajnoczi Signed-off-by: Miklos Szeredi --- fs/fuse/virtio_fs.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/fs/fuse/virtio_fs.c b/fs/fuse/virtio_fs.c index 8868ac31a3c0a1..4ee6f734ba8380 100644 --- a/fs/fuse/virtio_fs.c +++ b/fs/fuse/virtio_fs.c @@ -1324,8 +1324,15 @@ static int virtio_fs_fill_super(struct super_block *sb, struct fs_context *fsc) /* virtiofs allocates and installs its own fuse devices */ ctx->fudptr = NULL; - if (ctx->dax) + if (ctx->dax) { + if (!fs->dax_dev) { + err = -EINVAL; + pr_err("virtio-fs: dax can't be enabled as filesystem" + " device does not support it.\n"); + goto err_free_fuse_devs; + } ctx->dax_dev = fs->dax_dev; + } err = fuse_fill_super_common(sb, ctx); if (err < 0) goto err_free_fuse_devs;