[PATCH RFC v2 03/23] rnbd: use scoped_with_init_fs() for block device open

[Christian Brauner]

Use scoped_with_init_fs() to temporarily override current->fs for
the bdev_file_open_by_path() call so the path lookup happens in
init's filesystem context.

process_msg_open() ← rnbd_srv_rdma_ev() ← RDMA completion callback ←
ib_cq_poll_work() ← kworker (InfiniBand completion workqueue)

Signed-off-by: Christian Brauner <brauner@xxxxxxxxxx>
---
 drivers/block/rnbd/rnbd-srv.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/block/rnbd/rnbd-srv.c b/drivers/block/rnbd/rnbd-srv.c
index 10e8c438bb43..79c9a5fb418f 100644
--- a/drivers/block/rnbd/rnbd-srv.c
+++ b/drivers/block/rnbd/rnbd-srv.c
@@ -11,6 +11,7 @@
 
 #include <linux/module.h>
 #include <linux/blkdev.h>
+#include <linux/fs_struct.h>
 
 #include "rnbd-srv.h"
 #include "rnbd-srv-trace.h"
@@ -734,7 +735,8 @@ static int process_msg_open(struct rnbd_srv_session *srv_sess,
 		goto reject;
 	}
 
-	bdev_file = bdev_file_open_by_path(full_path, open_flags, NULL, NULL);
+	scoped_with_init_fs()
+		bdev_file = bdev_file_open_by_path(full_path, open_flags, NULL, NULL);
 	if (IS_ERR(bdev_file)) {
 		ret = PTR_ERR(bdev_file);
 		pr_err("Opening device '%s' on session %s failed, failed to open the block device, err: %pe\n",

-- 
2.47.3