ceph: warn on allocation from msgpool with larger front_len

Pass the front_len we need when pulling a message off a msgpool,
and WARN if it is greater than the pool's size.  Then try to
allocate a new message (to continue without failing).

Signed-off-by: Sage Weil <sage@newdream.net>

1 files changed, 17 insertions, 3 deletions

diff --git a/fs/ceph/msgpool.c b/fs/ceph/msgpool.c
index 39d4d7ed82ce..7599b3382076 100644
--- a/fs/ceph/msgpool.c
+++ b/fs/ceph/msgpool.c
@@ -101,14 +101,28 @@ int ceph_msgpool_resv(struct ceph_msgpool *pool, int delta)
         return ret;
 }
 
-struct ceph_msg *ceph_msgpool_get(struct ceph_msgpool *pool)
+struct ceph_msg *ceph_msgpool_get(struct ceph_msgpool *pool, int front_len)
 {
         wait_queue_t wait;
         struct ceph_msg *msg;
 
+        if (front_len && front_len > pool->front_len) {
+                pr_err("msgpool_get pool %p need front %d, pool size is %d\n",
+                       pool, front_len, pool->front_len);
+                WARN_ON(1);
+
+                /* try to alloc a fresh message */
+                msg = ceph_msg_new(0, front_len, 0, 0, NULL);
+                if (!IS_ERR(msg))
+                        return msg;
+        }
+
+        if (!front_len)
+                front_len = pool->front_len;
+
         if (pool->blocking) {
                 /* mempool_t behavior; first try to alloc */
-                msg = ceph_msg_new(0, pool->front_len, 0, 0, NULL);
+                msg = ceph_msg_new(0, front_len, 0, 0, NULL);
                 if (!IS_ERR(msg))
                         return msg;
         }
@@ -133,7 +147,7 @@ struct ceph_msg *ceph_msgpool_get(struct ceph_msgpool *pool)
                         WARN_ON(1);
 
                         /* maybe we can allocate it now? */
-                        msg = ceph_msg_new(0, pool->front_len, 0, 0, NULL);
+                        msg = ceph_msg_new(0, front_len, 0, 0, NULL);
                         if (!IS_ERR(msg))
                                 return msg;