fuse: add nocreds to fuse_args

In some cases it makes no sense to set pid/uid/gid fields in the request
header.  Allow fuse_simple_background() to omit these.  This is only
required in the "force" case, so for now just WARN if set otherwise.

Fold fuse_get_req_nofail_nopages() into its only caller.  Comment is
obsolete anyway.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index 19114b23e95f1969d60a28cc38d614fa8500d980..9f1549166a5d7ae1e619fc276a5aff9cb64063fd 100644 (file)
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -242,34 +242,6 @@ struct fuse_req *fuse_get_req_for_background(struct fuse_conn *fc,
 }
 EXPORT_SYMBOL_GPL(fuse_get_req_for_background);
 
-/*
- * Gets a requests for a file operation, always succeeds
- *
- * This is used for sending the FLUSH request, which must get to
- * userspace, due to POSIX locks which may need to be unlocked.
- *
- * If allocation fails due to OOM, use the reserved request in
- * fuse_file.
- *
- * This is very unlikely to deadlock accidentally, since the
- * filesystem should not have it's own file open.  If deadlock is
- * intentional, it can still be broken by "aborting" the filesystem.
- */
-static struct fuse_req *fuse_get_req_nofail_nopages(struct fuse_conn *fc)
-{
-       struct fuse_req *req;
-
-       atomic_inc(&fc->num_waiting);
-       req = __fuse_request_alloc(0, GFP_KERNEL | __GFP_NOFAIL);
-
-       req->in.h.uid = from_kuid_munged(fc->user_ns, current_fsuid());
-       req->in.h.gid = from_kgid_munged(fc->user_ns, current_fsgid());
-       req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns);
-
-       __set_bit(FR_WAITING, &req->flags);
-       return req;
-}
-
 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
 {
        if (refcount_dec_and_test(&req->count)) {
@@ -565,15 +537,29 @@ static void fuse_adjust_compat(struct fuse_conn *fc, struct fuse_args *args)
        }
 }
 
+static void fuse_force_creds(struct fuse_conn *fc, struct fuse_req *req)
+{
+       req->in.h.uid = from_kuid_munged(fc->user_ns, current_fsuid());
+       req->in.h.gid = from_kgid_munged(fc->user_ns, current_fsgid());
+       req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns);
+}
+
 ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args)
 {
        struct fuse_req *req;
        ssize_t ret;
 
        if (args->force) {
-               req = fuse_get_req_nofail_nopages(fc);
+               atomic_inc(&fc->num_waiting);
+               req = __fuse_request_alloc(0, GFP_KERNEL | __GFP_NOFAIL);
+
+               if (!args->nocreds)
+                       fuse_force_creds(fc, req);
+
+               __set_bit(FR_WAITING, &req->flags);
                __set_bit(FR_FORCE, &req->flags);
        } else {
+               WARN_ON(args->nocreds);
                req = fuse_get_req(fc, 0);
                if (IS_ERR(req))
                        return PTR_ERR(req);

diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index e6a8e47d0e0bb856ad1f7cac01a1a78e891d68cf..43ae5b7f4dd4e7ef7b7795806f2173f6f924bd15 100644 (file)
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -293,6 +293,7 @@ struct fuse_args {
        unsigned short out_numargs;
        bool force:1;
        bool noreply:1;
+       bool nocreds:1;
        bool out_argvar:1;
        struct fuse_in_arg in_args[3];
        struct fuse_arg out_args[2];