This patch introduces a new flag DLM_PLOCK_FL_NO_REPLY in case an dlm
plock operation should not send a reply back. Currently this is kind of
being handled in DLM_PLOCK_FL_CLOSE, but DLM_PLOCK_FL_CLOSE has more
meanings that it will remove all waiters for a specific nodeid/owner
values in by doing a unlock operation. In case of an error in dlm user
space software e.g. dlm_controld we get an reply with an error back.
This cannot be matched because there is no op to match in recv_list. We
filter now on DLM_PLOCK_FL_NO_REPLY in case we had an error back as
reply. In newer dlm_controld version it will never send a result back
when DLM_PLOCK_FL_NO_REPLY is set. This filter is a workaround to handle
older dlm_controld versions.
Fixes: 901025d2f319 ("dlm: make plock operation killable")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Alexander Aring <aahringo@xxxxxxxxxx>
---
fs/dlm/plock.c | 23 +++++++++++++++++++----
include/uapi/linux/dlm_plock.h | 1 +
2 files changed, 20 insertions(+), 4 deletions(-)
diff --git a/fs/dlm/plock.c b/fs/dlm/plock.c
index 70a4752ed913..7fe9f4b922d3 100644
--- a/fs/dlm/plock.c
+++ b/fs/dlm/plock.c
@@ -96,7 +96,7 @@ static void do_unlock_close(const struct dlm_plock_info *info)
op->info.end = OFFSET_MAX;
op->info.owner = info->owner;
- op->info.flags |= DLM_PLOCK_FL_CLOSE;
+ op->info.flags |= (DLM_PLOCK_FL_CLOSE | DLM_PLOCK_FL_NO_REPLY);
send_op(op);
}
@@ -293,7 +293,7 @@ int dlm_posix_unlock(dlm_lockspace_t *lockspace, u64 number, struct file *file,
op->info.owner = (__u64)(long) fl->fl_owner;
if (fl->fl_flags & FL_CLOSE) {
- op->info.flags |= DLM_PLOCK_FL_CLOSE;
+ op->info.flags |= (DLM_PLOCK_FL_CLOSE | DLM_PLOCK_FL_NO_REPLY);
send_op(op);
rv = 0;
goto out;
@@ -392,7 +392,7 @@ static ssize_t dev_read(struct file *file, char __user *u, size_t count,
spin_lock(&ops_lock);
if (!list_empty(&send_list)) {
op = list_first_entry(&send_list, struct plock_op, list);
- if (op->info.flags & DLM_PLOCK_FL_CLOSE)
+ if (op->info.flags & DLM_PLOCK_FL_NO_REPLY)
list_del(&op->list);
else
list_move_tail(&op->list, &recv_list);
@@ -407,7 +407,7 @@ static ssize_t dev_read(struct file *file, char __user *u, size_t count,
that were generated by the vfs cleaning up for a close
(the process did not make an unlock call). */
- if (op->info.flags & DLM_PLOCK_FL_CLOSE)
+ if (op->info.flags & DLM_PLOCK_FL_NO_REPLY)
dlm_release_plock_op(op);
if (copy_to_user(u, &info, sizeof(info)))
@@ -433,6 +433,21 @@ static ssize_t dev_write(struct file *file, const char __user *u, size_t count,
if (check_version(&info))
return -EINVAL;
+ /* Some old dlm user space software will send replies back,
+ * even if DLM_PLOCK_FL_NO_REPLY is set (because the flag is
+ * new) e.g. if a error occur. We can't match them in recv_list
+ * because they were never be part of it. We filter it here,
+ * new dlm user space software will filter it in user space.
+ *
+ * In future this handling can be removed.
+ */
+ if (info.flags & DLM_PLOCK_FL_NO_REPLY) {
+ pr_info("Received unexpected reply from op %d, "
+ "please update DLM user space software!\n",
+ info.optype);
+ return count;
+ }
+
/*
* The results for waiting ops (SETLKW) can be returned in any
* order, so match all fields to find the op. The results for
diff --git a/include/uapi/linux/dlm_plock.h b/include/uapi/linux/dlm_plock.h
index 63b6c1fd9169..8dfa272c929a 100644
--- a/include/uapi/linux/dlm_plock.h
+++ b/include/uapi/linux/dlm_plock.h
@@ -25,6 +25,7 @@ enum {
};
#define DLM_PLOCK_FL_CLOSE 1
+#define DLM_PLOCK_FL_NO_REPLY 2
struct dlm_plock_info {
__u32 version[3];
--
2.31.1
