Re: [PATCH 1/1] fuse: Handle no_open/no_opendir in atomic_open

[Bernd Schubert <bernd.schubert@fastmail.fm>]

On 11/29/23 07:46, Yuan Yao wrote:
> Currently, if the fuse server supporting the no_open/no_opendir feature
> uses atomic_open to open a file, the corresponding no_open/no_opendir
> flag is not set in kernel. This leads to the kernel unnecessarily
> sending extra FUSE_RELEASE request, receiving an empty reply from
> server when closes that file.
> 
> This patch addresses the issue by setting the no_open/no_opendir feature
> bit to true if the kernel receives a valid dentry with an empty file
> handler.
> 
> Signed-off-by: Yuan Yao <yuanyaogoog@chromium.org>
> ---
>   fs/fuse/dir.c | 8 ++++++++
>   1 file changed, 8 insertions(+)
> 
> diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
> index 9956fae7f875..edee4f715f39 100644
> --- a/fs/fuse/dir.c
> +++ b/fs/fuse/dir.c
> @@ -8,6 +8,7 @@
>   
>   #include "fuse_i.h"
>   
> +#include <linux/fuse.h>
>   #include <linux/pagemap.h>
>   #include <linux/file.h>
>   #include <linux/fs_context.h>
> @@ -869,6 +870,13 @@ static int _fuse_atomic_open(struct inode *dir, struct dentry *entry,
>   		goto out_err;
>   	}
>   
> +	if (ff->fh == 0) {
> +		if (ff->open_flags & FOPEN_KEEP_CACHE)
> +			fc->no_open = 1;
> +		if (ff->open_flags & FOPEN_CACHE_DIR)
> +			fc->no_opendir = 1;
> +	}
> +
>   	/* prevent racing/parallel lookup on a negative hashed */
>   	if (!(flags & O_CREAT) && !d_in_lookup(entry)) {
>   		d_drop(entry);


Thanks, I first need to fix all the issues Al found (and need to find 
the time for that, hopefully during the next days) and will then add 
this to my series.

(We also need to document for userspace that the atomic_open method 
shall not fill in fi->fh in atomic-open, if it wants the no-open feature).

Thanks,
Bernd