| Message ID | 20240913104703.1673180-1-mszeredi@redhat.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | fuse: allow O_PATH fd for FUSE_DEV_IOC_BACKING_OPEN | expand |
On Fri, Sep 13, 2024 at 12:50 PM Miklos Szeredi <mszeredi@redhat.com> wrote: > > Only f_path is used from backing files registered with > FUSE_DEV_IOC_BACKING_OPEN, so it makes sense to allow O_PATH descriptors. > > O_PATH files have an empty f_op, so don't check read_iter/write_iter. > > Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Agreed. Reviewed-by: Amir Goldstein <amir73il@gmail.com> > --- > fs/fuse/passthrough.c | 6 +----- > 1 file changed, 1 insertion(+), 5 deletions(-) > > diff --git a/fs/fuse/passthrough.c b/fs/fuse/passthrough.c > index 9666d13884ce..ba3207f6c4ce 100644 > --- a/fs/fuse/passthrough.c > +++ b/fs/fuse/passthrough.c > @@ -228,15 +228,11 @@ int fuse_backing_open(struct fuse_conn *fc, struct fuse_backing_map *map) > if (map->flags || map->padding) > goto out; > > - file = fget(map->fd); > + file = fget_raw(map->fd); > res = -EBADF; > if (!file) > goto out; > > - res = -EOPNOTSUPP; > - if (!file->f_op->read_iter || !file->f_op->write_iter) > - goto out_fput; > - FWIW, I have made those sanity checks opt-in in my fuse-backing-inode-wip branch: https://github.com/amir73il/linux/commit/24c9a87bb11d76414b85960c0e3638a655a9c9a1 But that could be added later. Thanks, Amir.
On Fri, 13 Sept 2024 at 13:05, Amir Goldstein <amir73il@gmail.com> wrote: > > On Fri, Sep 13, 2024 at 12:50 PM Miklos Szeredi <mszeredi@redhat.com> wrote: > > - res = -EOPNOTSUPP; > > - if (!file->f_op->read_iter || !file->f_op->write_iter) > > - goto out_fput; > > - > > FWIW, I have made those sanity checks opt-in in my > fuse-backing-inode-wip branch: > https://github.com/amir73il/linux/commit/24c9a87bb11d76414b85960c0e3638a655a9c9a1 > > But that could be added later. This is the wrong place to check the f_op. We could do it in backing_file_open(), but this isn't going to be a common error, so I guess just returning an error at read/write time is also okay. Thanks, Miklos
On Fri, Sep 13, 2024 at 1:13 PM Miklos Szeredi <miklos@szeredi.hu> wrote: > > On Fri, 13 Sept 2024 at 13:05, Amir Goldstein <amir73il@gmail.com> wrote: > > > > On Fri, Sep 13, 2024 at 12:50 PM Miklos Szeredi <mszeredi@redhat.com> wrote: > > > > - res = -EOPNOTSUPP; > > > - if (!file->f_op->read_iter || !file->f_op->write_iter) > > > - goto out_fput; > > > - > > > > FWIW, I have made those sanity checks opt-in in my > > fuse-backing-inode-wip branch: > > https://github.com/amir73il/linux/commit/24c9a87bb11d76414b85960c0e3638a655a9c9a1 > > > > But that could be added later. > > This is the wrong place to check the f_op. > > We could do it in backing_file_open(), but this isn't going to be a > common error, so I guess just returning an error at read/write time is > also okay. > Yeh. works for me. Thanks, Amir.
diff --git a/fs/fuse/passthrough.c b/fs/fuse/passthrough.c index 9666d13884ce..ba3207f6c4ce 100644 --- a/fs/fuse/passthrough.c +++ b/fs/fuse/passthrough.c @@ -228,15 +228,11 @@ int fuse_backing_open(struct fuse_conn *fc, struct fuse_backing_map *map) if (map->flags || map->padding) goto out; - file = fget(map->fd); + file = fget_raw(map->fd); res = -EBADF; if (!file) goto out; - res = -EOPNOTSUPP; - if (!file->f_op->read_iter || !file->f_op->write_iter) - goto out_fput; - backing_sb = file_inode(file)->i_sb; res = -ELOOP; if (backing_sb->s_stack_depth >= fc->max_stack_depth)
Only f_path is used from backing files registered with FUSE_DEV_IOC_BACKING_OPEN, so it makes sense to allow O_PATH descriptors. O_PATH files have an empty f_op, so don't check read_iter/write_iter. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> --- fs/fuse/passthrough.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-)