ceph: implement updated ceph_mds_request_head structure

When we added the btime feature in mainline ceph, we had to extend
struct ceph_mds_request_args so that it could be set. Implement the same
in the kernel client.

Rename ceph_mds_request_head with a _old extension, and a union
ceph_mds_request_args_ext to allow for the extended size of the new
header format.

Add the appropriate code to handle both formats in struct
create_request_message and key the behavior on whether the peer supports
CEPH_FEATURE_FS_BTIME.

The gid_list field in the payload is now populated from the saved
credential. For now, we don't add any support for setting the btime via
setattr, but this does enable us to add that in the future.

[ idryomov: break unnecessarily long lines ]

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

1 files changed, 62 insertions, 13 deletions

diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 14d0a11b7d88..a256d95ec99a 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -2478,21 +2478,24 @@ static int set_request_path_attr(struct inode *rinode, struct dentry *rdentry,
 /*
  * called under mdsc->mutex
  */
-static struct ceph_msg *create_request_message(struct ceph_mds_client *mdsc,
+static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
 					       struct ceph_mds_request *req,
-					       int mds, bool drop_cap_releases)
+					       bool drop_cap_releases)
 {
+	int mds = session->s_mds;
+	struct ceph_mds_client *mdsc = session->s_mdsc;
 	struct ceph_msg *msg;
-	struct ceph_mds_request_head *head;
+	struct ceph_mds_request_head_old *head;
 	const char *path1 = NULL;
 	const char *path2 = NULL;
 	u64 ino1 = 0, ino2 = 0;
 	int pathlen1 = 0, pathlen2 = 0;
 	bool freepath1 = false, freepath2 = false;
-	int len;
+	int len, i;
 	u16 releases;
 	void *p, *end;
 	int ret;
+	bool legacy = !(session->s_con.peer_features & CEPH_FEATURE_FS_BTIME);
 
 	ret = set_request_path_attr(req->r_inode, req->r_dentry,
 			      req->r_parent, req->r_path1, req->r_ino1.ino,
@@ -2514,14 +2517,23 @@ static struct ceph_msg *create_request_message(struct ceph_mds_client *mdsc,
 		goto out_free1;
 	}
 
-	len = sizeof(*head) +
-		pathlen1 + pathlen2 + 2*(1 + sizeof(u32) + sizeof(u64)) +
+	if (legacy) {
+		/* Old style */
+		len = sizeof(*head);
+	} else {
+		/* New style: add gid_list and any later fields */
+		len = sizeof(struct ceph_mds_request_head) + sizeof(u32) +
+		      (sizeof(u64) * req->r_cred->group_info->ngroups);
+	}
+
+	len += pathlen1 + pathlen2 + 2*(1 + sizeof(u32) + sizeof(u64)) +
 		sizeof(struct ceph_timespec);
 
 	/* calculate (max) length for cap releases */
 	len += sizeof(struct ceph_mds_request_release) *
 		(!!req->r_inode_drop + !!req->r_dentry_drop +
 		 !!req->r_old_inode_drop + !!req->r_old_dentry_drop);
+
 	if (req->r_dentry_drop)
 		len += pathlen1;
 	if (req->r_old_dentry_drop)
@@ -2533,11 +2545,25 @@ static struct ceph_msg *create_request_message(struct ceph_mds_client *mdsc,
 		goto out_free2;
 	}
 
-	msg->hdr.version = cpu_to_le16(3);
 	msg->hdr.tid = cpu_to_le64(req->r_tid);
 
-	head = msg->front.iov_base;
-	p = msg->front.iov_base + sizeof(*head);
+	/*
+	 * The old ceph_mds_request_header didn't contain a version field, and
+	 * one was added when we moved the message version from 3->4.
+	 */
+	if (legacy) {
+		msg->hdr.version = cpu_to_le16(3);
+		head = msg->front.iov_base;
+		p = msg->front.iov_base + sizeof(*head);
+	} else {
+		struct ceph_mds_request_head *new_head = msg->front.iov_base;
+
+		msg->hdr.version = cpu_to_le16(4);
+		new_head->version = cpu_to_le16(CEPH_MDS_REQUEST_HEAD_VERSION);
+		head = (struct ceph_mds_request_head_old *)&new_head->oldest_client_tid;
+		p = msg->front.iov_base + sizeof(*new_head);
+	}
+
 	end = msg->front.iov_base + msg->front.iov_len;
 
 	head->mdsmap_epoch = cpu_to_le32(mdsc->mdsmap->m_epoch);
@@ -2590,6 +2616,14 @@ static struct ceph_msg *create_request_message(struct ceph_mds_client *mdsc,
 		ceph_encode_copy(&p, &ts, sizeof(ts));
 	}
 
+	/* gid list */
+	if (!legacy) {
+		ceph_encode_32(&p, req->r_cred->group_info->ngroups);
+		for (i = 0; i < req->r_cred->group_info->ngroups; i++)
+			ceph_encode_64(&p, from_kgid(&init_user_ns,
+				       req->r_cred->group_info->gid[i]));
+	}
+
 	if (WARN_ON_ONCE(p > end)) {
 		ceph_msg_put(msg);
 		msg = ERR_PTR(-ERANGE);
@@ -2633,6 +2667,18 @@ static void complete_request(struct ceph_mds_client *mdsc,
 	complete_all(&req->r_completion);
 }
 
+static struct ceph_mds_request_head_old *
+find_old_request_head(void *p, u64 features)
+{
+	bool legacy = !(features & CEPH_FEATURE_FS_BTIME);
+	struct ceph_mds_request_head *new_head;
+
+	if (legacy)
+		return (struct ceph_mds_request_head_old *)p;
+	new_head = (struct ceph_mds_request_head *)p;
+	return (struct ceph_mds_request_head_old *)&new_head->oldest_client_tid;
+}
+
 /*
  * called under mdsc->mutex
  */
@@ -2642,7 +2688,7 @@ static int __prepare_send_request(struct ceph_mds_session *session,
 {
 	int mds = session->s_mds;
 	struct ceph_mds_client *mdsc = session->s_mdsc;
-	struct ceph_mds_request_head *rhead;
+	struct ceph_mds_request_head_old *rhead;
 	struct ceph_msg *msg;
 	int flags = 0;
 
@@ -2661,6 +2707,7 @@ static int __prepare_send_request(struct ceph_mds_session *session,
 
 	if (test_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags)) {
 		void *p;
+
 		/*
 		 * Replay.  Do not regenerate message (and rebuild
 		 * paths, etc.); just use the original message.
@@ -2668,7 +2715,8 @@ static int __prepare_send_request(struct ceph_mds_session *session,
 		 * d_move mangles the src name.
 		 */
 		msg = req->r_request;
-		rhead = msg->front.iov_base;
+		rhead = find_old_request_head(msg->front.iov_base,
+					      session->s_con.peer_features);
 
 		flags = le32_to_cpu(rhead->flags);
 		flags |= CEPH_MDS_FLAG_REPLAY;
@@ -2699,14 +2747,15 @@ static int __prepare_send_request(struct ceph_mds_session *session,
 		ceph_msg_put(req->r_request);
 		req->r_request = NULL;
 	}
-	msg = create_request_message(mdsc, req, mds, drop_cap_releases);
+	msg = create_request_message(session, req, drop_cap_releases);
 	if (IS_ERR(msg)) {
 		req->r_err = PTR_ERR(msg);
 		return PTR_ERR(msg);
 	}
 	req->r_request = msg;
 
-	rhead = msg->front.iov_base;
+	rhead = find_old_request_head(msg->front.iov_base,
+				      session->s_con.peer_features);
 	rhead->oldest_client_tid = cpu_to_le64(__get_oldest_tid(mdsc));
 	if (test_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags))
 		flags |= CEPH_MDS_FLAG_REPLAY;