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 <[email protected]> --- fs/fuse/virtio_fs.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) Index: redhat-linux/fs/fuse/virtio_fs.c =================================================================== --- redhat-linux.orig/fs/fuse/virtio_fs.c 2021-02-04 10:40:21.704370721 -0500 +++ redhat-linux/fs/fuse/virtio_fs.c 2021-02-09 15:56:45.693653979 -0500 @@ -1324,8 +1324,15 @@ static int virtio_fs_fill_super(struct s /* 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; _______________________________________________ Virtio-fs mailing list [email protected] https://www.redhat.com/mailman/listinfo/virtio-fs
