CacheFiles: Better showing of debugging information in active object problems

[mv-sheeva.git] / fs / cachefiles / namei.c

diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c
index 3df86952ca645c574fcf71d22327c27c6a345a0d..00a0cda8f47a39bcf984770c74cc8fd37ff1a826 100644 (file)
--- a/fs/cachefiles/namei.c
+++ b/fs/cachefiles/namei.c
@@ -27,6 +27,76 @@ static int cachefiles_wait_bit(void *flags)
        return 0;
 }
 
+#define CACHEFILES_KEYBUF_SIZE 512
+
+/*
+ * dump debugging info about an object
+ */
+static noinline
+void __cachefiles_printk_object(struct cachefiles_object *object,
+                               const char *prefix,
+                               u8 *keybuf)
+{
+       struct fscache_cookie *cookie;
+       unsigned keylen, loop;
+
+       printk(KERN_ERR "%sobject: OBJ%x\n",
+              prefix, object->fscache.debug_id);
+       printk(KERN_ERR "%sobjstate=%s fl=%lx swfl=%lx ev=%lx[%lx]\n",
+              prefix, fscache_object_states[object->fscache.state],
+              object->fscache.flags, object->fscache.work.flags,
+              object->fscache.events,
+              object->fscache.event_mask & FSCACHE_OBJECT_EVENTS_MASK);
+       printk(KERN_ERR "%sops=%u inp=%u exc=%u\n",
+              prefix, object->fscache.n_ops, object->fscache.n_in_progress,
+              object->fscache.n_exclusive);
+       printk(KERN_ERR "%sparent=%p\n",
+              prefix, object->fscache.parent);
+
+       spin_lock(&object->fscache.lock);
+       cookie = object->fscache.cookie;
+       if (cookie) {
+               printk(KERN_ERR "%scookie=%p [pr=%p nd=%p fl=%lx]\n",
+                      prefix,
+                      object->fscache.cookie,
+                      object->fscache.cookie->parent,
+                      object->fscache.cookie->netfs_data,
+                      object->fscache.cookie->flags);
+               if (keybuf)
+                       keylen = cookie->def->get_key(cookie->netfs_data, keybuf,
+                                                     CACHEFILES_KEYBUF_SIZE);
+               else
+                       keylen = 0;
+       } else {
+               printk(KERN_ERR "%scookie=NULL\n", prefix);
+               keylen = 0;
+       }
+       spin_unlock(&object->fscache.lock);
+
+       if (keylen) {
+               printk(KERN_ERR "%skey=[%u] '", prefix, keylen);
+               for (loop = 0; loop < keylen; loop++)
+                       printk("%02x", keybuf[loop]);
+               printk("'\n");
+       }
+}
+
+/*
+ * dump debugging info about a pair of objects
+ */
+static noinline void cachefiles_printk_object(struct cachefiles_object *object,
+                                             struct cachefiles_object *xobject)
+{
+       u8 *keybuf;
+
+       keybuf = kmalloc(CACHEFILES_KEYBUF_SIZE, GFP_NOIO);
+       if (object)
+               __cachefiles_printk_object(object, "", keybuf);
+       if (xobject)
+               __cachefiles_printk_object(xobject, "x", keybuf);
+       kfree(keybuf);
+}
+
 /*
  * record the fact that an object is now active
  */
@@ -42,8 +112,11 @@ static void cachefiles_mark_object_active(struct cachefiles_cache *cache,
 try_again:
        write_lock(&cache->active_lock);
 
-       if (test_and_set_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags))
+       if (test_and_set_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags)) {
+               printk(KERN_ERR "CacheFiles: Error: Object already active\n");
+               cachefiles_printk_object(object, NULL);
                BUG();
+       }
 
        dentry = object->dentry;
        _p = &cache->active_nodes.rb_node;
@@ -76,32 +149,7 @@ wait_for_old_object:
                printk(KERN_ERR "\n");
                printk(KERN_ERR "CacheFiles: Error:"
                       " Unexpected object collision\n");
-               printk(KERN_ERR "xobject: OBJ%x\n",
-                      xobject->fscache.debug_id);
-               printk(KERN_ERR "xobjstate=%s\n",
-                      fscache_object_states[xobject->fscache.state]);
-               printk(KERN_ERR "xobjflags=%lx\n", xobject->fscache.flags);
-               printk(KERN_ERR "xobjevent=%lx [%lx]\n",
-                      xobject->fscache.events, xobject->fscache.event_mask);
-               printk(KERN_ERR "xops=%u inp=%u exc=%u\n",
-                      xobject->fscache.n_ops, xobject->fscache.n_in_progress,
-                      xobject->fscache.n_exclusive);
-               printk(KERN_ERR "xcookie=%p [pr=%p nd=%p fl=%lx]\n",
-                      xobject->fscache.cookie,
-                      xobject->fscache.cookie->parent,
-                      xobject->fscache.cookie->netfs_data,
-                      xobject->fscache.cookie->flags);
-               printk(KERN_ERR "xparent=%p\n",
-                      xobject->fscache.parent);
-               printk(KERN_ERR "object: OBJ%x\n",
-                      object->fscache.debug_id);
-               printk(KERN_ERR "cookie=%p [pr=%p nd=%p fl=%lx]\n",
-                      object->fscache.cookie,
-                      object->fscache.cookie->parent,
-                      object->fscache.cookie->netfs_data,
-                      object->fscache.cookie->flags);
-               printk(KERN_ERR "parent=%p\n",
-                      object->fscache.parent);
+               cachefiles_printk_object(object, xobject);
                BUG();
        }
        atomic_inc(&xobject->usage);