[PATCH AUTOSEL 4.19 2/2] nvmet: seset ns->file when open fails

From: Sasha Levin
Date: Mon May 17 2021 - 21:10:41 EST

From: Daniel Wagner <dwagner@xxxxxxx>

[ Upstream commit 85428beac80dbcace5b146b218697c73e367dcf5 ]

Reset the ns->file value to NULL also in the error case in

The ns->file variable points either to file object or contains the
error code after the filp_open() call. This can lead to following

When the user first setups an invalid file backend and tries to enable
the ns, it will fail. Then the user switches over to a bdev backend
and enables successfully the ns. The first received I/O will crash the
system because the IO backend is chosen based on the ns->file value:

static u16 nvmet_parse_io_cmd(struct nvmet_req *req)

if (req->ns->file)
return nvmet_file_parse_io_cmd(req);

return nvmet_bdev_parse_io_cmd(req);

Reported-by: Enzo Matsumiya <ematsumiya@xxxxxxxx>
Signed-off-by: Daniel Wagner <dwagner@xxxxxxx>
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
drivers/nvme/target/io-cmd-file.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/nvme/target/io-cmd-file.c b/drivers/nvme/target/io-cmd-file.c
index 39d972e2595f..ad6263cf7303 100644
--- a/drivers/nvme/target/io-cmd-file.c
+++ b/drivers/nvme/target/io-cmd-file.c
@@ -38,9 +38,11 @@ int nvmet_file_ns_enable(struct nvmet_ns *ns)

ns->file = filp_open(ns->device_path, flags, 0);
if (IS_ERR(ns->file)) {
- pr_err("failed to open file %s: (%ld)\n",
- ns->device_path, PTR_ERR(ns->file));
- return PTR_ERR(ns->file);
+ ret = PTR_ERR(ns->file);
+ pr_err("failed to open file %s: (%d)\n",
+ ns->device_path, ret);
+ ns->file = NULL;
+ return ret;

ret = vfs_getattr(&ns->file->f_path,