Notify user daemon that cookie is going to be withdrawn, providing a
hint that the associated anon_fd can be closed. The anon_fd attached in
the CLOSE request shall be same with that in the previous OPEN request.
Be noted that this is only a hint. User daemon can close the anon_fd
when receiving the CLOSE request, then it will receive another anon_fd
if the cookie gets looked up. Or it can also ignore the CLOSE request,
and keep writing data into the anon_fd. However the next time cookie
gets looked up, the user daemon will still receive another anon_fd.
Signed-off-by: Jeffle Xu <jefflexu@xxxxxxxxxxxxxxxxx>
---
fs/cachefiles/interface.c | 2 ++
fs/cachefiles/internal.h | 5 +++++
fs/cachefiles/ondemand.c | 36 +++++++++++++++++++++++++++++++++
include/uapi/linux/cachefiles.h | 5 +++++
4 files changed, 48 insertions(+)
diff --git a/fs/cachefiles/interface.c b/fs/cachefiles/interface.c
index ae93cee9d25d..a69073a1d3f0 100644
--- a/fs/cachefiles/interface.c
+++ b/fs/cachefiles/interface.c
@@ -362,6 +362,8 @@ static void cachefiles_withdraw_cookie(struct fscache_cookie *cookie)
spin_unlock(&cache->object_list_lock);
}
+ cachefiles_ondemand_clean_object(object);
+
if (object->file) {
cachefiles_begin_secure(cache, &saved_cred);
cachefiles_clean_up_object(object, cache);
diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h
index 7d5c7d391fdb..8a397d4da560 100644
--- a/fs/cachefiles/internal.h
+++ b/fs/cachefiles/internal.h
@@ -279,6 +279,7 @@ extern int cachefiles_ondemand_copen(struct cachefiles_cache *cache,
char *args);
extern int cachefiles_ondemand_init_object(struct cachefiles_object *object);
+extern void cachefiles_ondemand_clean_object(struct cachefiles_object *object);
#else
static inline ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache,
@@ -291,6 +292,10 @@ static inline int cachefiles_ondemand_init_object(struct cachefiles_object *obje
{
return 0;
}
+
+static inline void cachefiles_ondemand_clean_object(struct cachefiles_object *object)
+{
+}
#endif
/*
diff --git a/fs/cachefiles/ondemand.c b/fs/cachefiles/ondemand.c
index 75180d02af91..defd65124052 100644
--- a/fs/cachefiles/ondemand.c
+++ b/fs/cachefiles/ondemand.c
@@ -213,6 +213,12 @@ ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache,
goto err_put_fd;
}
+ /* CLOSE request has no reply */
+ if (msg->opcode == CACHEFILES_OP_CLOSE) {
+ xa_erase(&cache->reqs, id);
+ complete(&req->done);
+ }
+
return n;
err_put_fd:
@@ -334,6 +340,28 @@ static int init_open_req(struct cachefiles_req *req, void *private)
return 0;
}
+static int init_close_req(struct cachefiles_req *req, void *private)
+{
+ struct cachefiles_object *object = req->object;
+ struct cachefiles_close *load = (void *)req->msg.data;
+ int fd = object->fd;
+
+ if (fd == -1) {
+ pr_info_once("CLOSE: anonymous fd closed prematurely.\n");
+ return -EIO;
+ }
+
+ /*
+ * It's possible if the cookie looking up phase failed before READ
+ * request has ever been sent.
+ */
+ if (fd == 0)
+ return -ENOENT;
+
+ load->fd = fd;
+ return 0;
+}
+
int cachefiles_ondemand_init_object(struct cachefiles_object *object)
{
struct fscache_cookie *cookie = object->cookie;
@@ -358,3 +386,11 @@ int cachefiles_ondemand_init_object(struct cachefiles_object *object)
CACHEFILES_OP_OPEN, data_len,
init_open_req, NULL);
}
+
+void cachefiles_ondemand_clean_object(struct cachefiles_object *object)
+{
+ cachefiles_ondemand_send_req(object,
+ CACHEFILES_OP_CLOSE,
+ sizeof(struct cachefiles_close),
+ init_close_req, NULL);
+}
diff --git a/include/uapi/linux/cachefiles.h b/include/uapi/linux/cachefiles.h
index 41492f2653c9..73397e142ab3 100644
--- a/include/uapi/linux/cachefiles.h
+++ b/include/uapi/linux/cachefiles.h
@@ -12,6 +12,7 @@
enum cachefiles_opcode {
CACHEFILES_OP_OPEN,
+ CACHEFILES_OP_CLOSE,
};
/*
@@ -46,4 +47,8 @@ struct cachefiles_open {
__u8 data[];
};
+struct cachefiles_close {
+ __u32 fd;
+};
+
#endif
--
2.27.0
