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authorDavid Howells <dhowells@redhat.com>2009-11-19 18:12:02 +0000
committerDavid Howells <dhowells@redhat.com>2009-11-19 18:12:02 +0000
commitd0e27b7808dc667f3015be0b6888f6d680e222c8 (patch)
treebf8451f0d9a95db14ed1ebda50d701f4f387c0d8
parent6511de33c877a53b3df545bc06c29e0f272837ff (diff)
downloadop-kernel-dev-d0e27b7808dc667f3015be0b6888f6d680e222c8.zip
op-kernel-dev-d0e27b7808dc667f3015be0b6888f6d680e222c8.tar.gz
CacheFiles: Better showing of debugging information in active object problems
Show more debugging information if cachefiles_mark_object_active() is asked to activate an active object. This may happen, for instance, if the netfs tries to register an object with the same key multiple times. The code is changed to (a) get the appropriate object lock to protect the cookie pointer whilst we dereference it, and (b) get and display the cookie key if available. Signed-off-by: David Howells <dhowells@redhat.com>
-rw-r--r--fs/cachefiles/namei.c102
1 files changed, 75 insertions, 27 deletions
diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c
index 3df8695..00a0cda 100644
--- 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);
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