Commit 3f9b9efd authored by Vivek Goyal's avatar Vivek Goyal Committed by Miklos Szeredi
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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: default avatarVivek Goyal <vgoyal@redhat.com>
Reviewed-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
parent 775c5033

fs/fuse/virtio_fs.c

+8 −1
Original line number Diff line number Diff line
@@ -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;