[PATCH] ocfs2: insure dlm lockspace is created by kernel module

From: Gang He
Date: Fri May 20 2016 - 04:12:16 EST


This patch will be used to insure the dlm lockspace is created by kernel
module when mounting a ocfs2 file system. There are two ways to create a
lockspace, from user space and kernel space, but the same name lockspaces
probably have different lvblen lengths/flags.
To avoid this mix using, we add one more flag DLM_LSFL_NEWEXCL, it will make
sure the dlm lockspace is created by kernel module when mounting.
Secondly, if a user space program (ocfs2-tools) is running on a file system,
the user tries to mount this file system in the cluster, DLM module will return
a -EEXIST or -EPROTO errno, we should give the user a obvious error message,
then, the user can let that user space tool exit before mounting the file
system again.

Signed-off-by: Gang He <ghe@xxxxxxxx>
---
fs/ocfs2/stack_user.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/fs/ocfs2/stack_user.c b/fs/ocfs2/stack_user.c
index ced70c8..c9e828e 100644
--- a/fs/ocfs2/stack_user.c
+++ b/fs/ocfs2/stack_user.c
@@ -1007,10 +1007,17 @@ static int user_cluster_connect(struct ocfs2_cluster_connection *conn)
lc->oc_type = NO_CONTROLD;

rc = dlm_new_lockspace(conn->cc_name, conn->cc_cluster_name,
- DLM_LSFL_FS, DLM_LVB_LEN,
+ DLM_LSFL_FS | DLM_LSFL_NEWEXCL, DLM_LVB_LEN,
&ocfs2_ls_ops, conn, &ops_rv, &fsdlm);
- if (rc)
+ if (rc) {
+ if (rc == -EEXIST || rc == -EPROTO)
+ printk(KERN_ERR "ocfs2: Unable to create the "
+ "lockspace %s (%d), because a ocfs2-tools "
+ "program is running on this file system "
+ "with the same name lockspace\n",
+ conn->cc_name, rc);
goto out;
+ }

if (ops_rv == -EOPNOTSUPP) {
lc->oc_type = WITH_CONTROLD;
--
1.8.5.6