ceph: set osdmap epoch for setxattr

When setting the file/dir layout, it may need data pool info. So
in mds server, it needs to check the osdmap. At present, if mds
doesn't find the data pool specified, it will try to get the latest
osdmap. Now if pass the osd epoch for setxattr, the mds server can
only check this epoch of osdmap.

URL: https://tracker.ceph.com/issues/48504
Signed-off-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

fs/ceph/mds_client.c

@@ -2533,7 +2533,7 @@ static struct ceph_msg *create_request_message(struct ceph_mds_client *mdsc,
 		goto out_free2;
 	}
 
-	msg->hdr.version = cpu_to_le16(2);
+	msg->hdr.version = cpu_to_le16(3);
 	msg->hdr.tid = cpu_to_le64(req->r_tid);
 
 	head = msg->front.iov_base;

fs/ceph/xattr.c

@@ -1022,6 +1022,7 @@ static int ceph_sync_setxattr(struct inode *inode, const char *name,
 	struct ceph_inode_info *ci = ceph_inode(inode);
 	struct ceph_mds_request *req;
 	struct ceph_mds_client *mdsc = fsc->mdsc;
+	struct ceph_osd_client *osdc = &fsc->client->osdc;
 	struct ceph_pagelist *pagelist = NULL;
 	int op = CEPH_MDS_OP_SETXATTR;
 	int err;
@@ -1060,6 +1061,8 @@ static int ceph_sync_setxattr(struct inode *inode, const char *name,
 
 	if (op == CEPH_MDS_OP_SETXATTR) {
 		req->r_args.setxattr.flags = cpu_to_le32(flags);
+		req->r_args.setxattr.osdmap_epoch =
+			cpu_to_le32(osdc->osdmap->epoch);
 		req->r_pagelist = pagelist;
 		pagelist = NULL;
 	}

include/linux/ceph/ceph_fs.h

@@ -424,6 +424,7 @@ union ceph_mds_request_args {
 	} __attribute__ ((packed)) open;
 	struct {
 		__le32 flags;
+		__le32 osdmap_epoch; /* used for setting file/dir layouts */
 	} __attribute__ ((packed)) setxattr;
 	struct {
 		struct ceph_file_layout_legacy layout;