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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  Comment is
obsolete anyway.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>
This commit is contained in:
Miklos Szeredi 2019-09-10 15:04:08 +02:00
parent 3545fe2112
commit e413754b26
2 changed files with 16 additions and 29 deletions
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44
fs/fuse/dev.c
View File

@ -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);

1
fs/fuse/fuse_i.h
View File

@ -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];