[PATCH 2/4] ceph: validate cluster FSID for new device syntax

[Venky Shankar <vshankar@xxxxxxxxxx>]

The new device syntax requires the cluster FSID as part
of the device string. Use this FSID to verify if it matches
the cluster FSID we get back from the monitor, failing the
mount on mismatch.

Signed-off-by: Venky Shankar <vshankar@xxxxxxxxxx>
---
 fs/ceph/super.c              | 9 +++++++++
 fs/ceph/super.h              | 1 +
 include/linux/ceph/libceph.h | 1 +
 net/ceph/ceph_common.c       | 3 ++-
 4 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/fs/ceph/super.c b/fs/ceph/super.c
index 950a28ad9c59..84bc06e51680 100644
--- a/fs/ceph/super.c
+++ b/fs/ceph/super.c
@@ -266,6 +266,9 @@ static int ceph_parse_new_source(const char *dev_name, const char *dev_name_end,
 	if (!fs_name_start)
 		return invalfc(fc, "missing file system name");
 
+	if (parse_fsid(fsid_start, &fsopt->fsid))
+		return invalfc(fc, "invalid fsid format");
+
 	++fs_name_start; /* start of file system name */
 	fsopt->mds_namespace = kstrndup(fs_name_start,
 					dev_name_end - fs_name_start, GFP_KERNEL);
@@ -748,6 +751,12 @@ static struct ceph_fs_client *create_fs_client(struct ceph_mount_options *fsopt,
 	}
 	opt = NULL; /* fsc->client now owns this */
 
+	/* help learn fsid */
+	if (fsopt->new_dev_syntax) {
+		ceph_check_fsid(fsc->client, &fsopt->fsid);
+		fsc->client->have_fsid = true;
+	}
+
 	fsc->client->extra_mon_dispatch = extra_mon_dispatch;
 	ceph_set_opt(fsc->client, ABORT_ON_FULL);
 
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index 557348ff3203..cfd8ec25a9a8 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -100,6 +100,7 @@ struct ceph_mount_options {
 	char *server_path;    /* default NULL (means "/") */
 	char *fscache_uniq;   /* default NULL */
 	char *mon_addr;
+	struct ceph_fsid fsid;
 };
 
 struct ceph_fs_client {
diff --git a/include/linux/ceph/libceph.h b/include/linux/ceph/libceph.h
index 409d8c29bc4f..24c1f4e9144d 100644
--- a/include/linux/ceph/libceph.h
+++ b/include/linux/ceph/libceph.h
@@ -296,6 +296,7 @@ extern bool libceph_compatible(void *data);
 extern const char *ceph_msg_type_name(int type);
 extern int ceph_check_fsid(struct ceph_client *client, struct ceph_fsid *fsid);
 extern void *ceph_kvmalloc(size_t size, gfp_t flags);
+extern int parse_fsid(const char *str, struct ceph_fsid *fsid);
 
 struct fs_parameter;
 struct fc_log;
diff --git a/net/ceph/ceph_common.c b/net/ceph/ceph_common.c
index 97d6ea763e32..db21734462a4 100644
--- a/net/ceph/ceph_common.c
+++ b/net/ceph/ceph_common.c
@@ -217,7 +217,7 @@ void *ceph_kvmalloc(size_t size, gfp_t flags)
 	return p;
 }
 
-static int parse_fsid(const char *str, struct ceph_fsid *fsid)
+int parse_fsid(const char *str, struct ceph_fsid *fsid)
 {
 	int i = 0;
 	char tmp[3];
@@ -247,6 +247,7 @@ static int parse_fsid(const char *str, struct ceph_fsid *fsid)
 	dout("parse_fsid ret %d got fsid %pU\n", err, fsid);
 	return err;
 }
+EXPORT_SYMBOL(parse_fsid);
 
 /*
  * ceph options
-- 
2.27.0