[PATCH] ceph: discard r_new_inode if open O_CREAT opened existing inode

[Jeff Layton <jlayton@kernel.org>]

When we do an unchecked create, we optimistically pre-create an inode
and populate it, including its fscrypt context. It's possible though
that we'll end up opening an existing inode, in which case the
precreated inode will have a crypto context that doesn't match the
existing data.

If we're issuing an O_CREAT open and find an existing inode, just
discard the precreated inode and create a new one to ensure the context
is properly set.

Cc: Luís Henriques <lhenriques@suse.de>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 fs/ceph/mds_client.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 840a60b812fc..b03128fdbb07 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -3504,13 +3504,19 @@ static void handle_reply(struct ceph_mds_session *session, struct ceph_msg *msg)
 	/* Must find target inode outside of mutexes to avoid deadlocks */
 	rinfo = &req->r_reply_info;
 	if ((err >= 0) && rinfo->head->is_target) {
-		struct inode *in;
+		struct inode *in = xchg(&req->r_new_inode, NULL);
 		struct ceph_vino tvino = {
 			.ino  = le64_to_cpu(rinfo->targeti.in->ino),
 			.snap = le64_to_cpu(rinfo->targeti.in->snapid)
 		};
 
-		in = ceph_get_inode(mdsc->fsc->sb, tvino, xchg(&req->r_new_inode, NULL));
+		/* If we ended up opening an existing inode, discard r_new_inode */
+		if (req->r_op == CEPH_MDS_OP_CREATE && !req->r_reply_info.has_create_ino) {
+			iput(in);
+			in = NULL;
+		}
+
+		in = ceph_get_inode(mdsc->fsc->sb, tvino, in);
 		if (IS_ERR(in)) {
 			err = PTR_ERR(in);
 			mutex_lock(&session->s_mutex);
-- 
2.35.1