[DLM] break from snprintf loop

When the debug buffer has filled up, break from the loop and return the
correct number of bytes that have been written.

Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

1 files changed, 7 insertions, 4 deletions

diff --git a/fs/dlm/debug_fs.c b/fs/dlm/debug_fs.c
index 8f471d9a9e3a..9c3aeddc8667 100644
--- a/fs/dlm/debug_fs.c
+++ b/fs/dlm/debug_fs.c
@@ -310,16 +310,19 @@ static ssize_t waiters_read(struct file *file, char __user *userbuf,
 {
         struct dlm_ls *ls = file->private_data;
         struct dlm_lkb *lkb;
-        size_t len = DLM_DEBUG_BUF_LEN, pos = 0, rv;
+        size_t len = DLM_DEBUG_BUF_LEN, pos = 0, ret, rv;
 
         mutex_lock(&debug_buf_lock);
         mutex_lock(&ls->ls_waiters_mutex);
         memset(debug_buf, 0, sizeof(debug_buf));
 
         list_for_each_entry(lkb, &ls->ls_waiters, lkb_wait_reply) {
-                pos += snprintf(debug_buf + pos, len - pos, "%x %d %d %s\n",
-                                lkb->lkb_id, lkb->lkb_wait_type,
-                                lkb->lkb_nodeid, lkb->lkb_resource->res_name);
+                ret = snprintf(debug_buf + pos, len - pos, "%x %d %d %s\n",
+                               lkb->lkb_id, lkb->lkb_wait_type,
+                               lkb->lkb_nodeid, lkb->lkb_resource->res_name);
+                if (ret >= len - pos)
+                        break;
+                pos += ret;
         }
         mutex_unlock(&ls->ls_waiters_mutex);