Re: [PATCH] fuse: add fusex filesystem

[Horst Birthelmer <horst@birthelmer.de>]

On Wed, Apr 29, 2026 at 12:20:57PM +0200, Miklos Szeredi wrote:
> This stands for "fuse extended/experimental".
> 
> The purpose is to provide a clean base for big features like the FUSE_IOMAP
> api.
> 
> It's also a good way to try new stuff like file handles and compound
> requests without the risk of breaking something in the large and complex
> fuse codebase.
> 
> Whether these features will be migrated back into the main fuse codebase,
> or fusex is going to end up as a major version update is still up in the
> air.
> 
> Major differences from regular fuse:
> 
>  - local filesystem mode only
>  - only synchronous FUSE_INIT is supported
>  - only no-open mode
>  - new requests:
>    + FUSE_LOOKUP_ROOT - return nodeid of root
>    + FUSE_LOOKUPX - FUSE_LOOKUP without the getattr
>    + FUSE_MKOBJX - merged FUSE_MKNOD, MKDIR, SYMLINK and TMPFILE
>    + FUSE_SETSTATX - extended version of FUSE_SETATTR
> 
> Missing features:
> 
>  - file handles / export ops
>  - compound requests
>  - xattr caching
>  - fileattr
>  - fiemap
>  - ioctl
>  - copy_file_range
>  - lazy dir open
> 
> Test server can be found at:
> 
>   https://github.com/szmi/fuse-utils
> 
> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
> ---
> 

Hi Miklos,

I have patched passthrough_hp to use fusex and have noticed, that I had to do
the following to make it work:

diff --git a/fs/fuse/fusex.c b/fs/fuse/fusex.c
index 98e239e7e00e..87fcfc16645a 100644
--- a/fs/fuse/fusex.c
+++ b/fs/fuse/fusex.c
@@ -14,6 +14,7 @@
 #include <linux/statfs.h>
 #include <linux/falloc.h>
 #include <linux/fs_parser.h>
+#include <uapi/linux/magic.h>
 
 static void fusex_init_inode(struct inode *inode);
 
@@ -1337,6 +1338,7 @@ static int fusex_send_opendir(struct fuse_file *ff, struct inode *inode)
        if (!err) {
                ff->fh = outarg.fh;
                ff->open_flags = FOPEN_CACHE_DIR;
+               ff->nodeid = get_node_id(inode);
        }
        return err;
 }

---


After that I could actually mount and do simple meta operations.
The nodeid is used for listing.

Thanks,
Horst