cachefiles: Trace active-mark failure

Add a tracepoint to log failure to apply an active mark to a file in
addition to tracing successfully setting and unsetting the mark.

Also include the backing file inode number in the message logged to dmesg.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/164251404666.3435901.17331742792401482190.stgit@warthog.procyon.org.uk/

diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c
index 52c9f08..f256c8a 100644 (file)
--- a/fs/cachefiles/namei.c
+++ b/fs/cachefiles/namei.c
@@ -25,7 +25,9 @@ static bool __cachefiles_mark_inode_in_use(struct cachefiles_object *object,
                trace_cachefiles_mark_active(object, inode);
                can_use = true;
        } else {
-               pr_notice("cachefiles: Inode already in use: %pd\n", dentry);
+               trace_cachefiles_mark_failed(object, inode);
+               pr_notice("cachefiles: Inode already in use: %pd (B=%lx)\n",
+                         dentry, inode->i_ino);
        }
 
        return can_use;

diff --git a/include/trace/events/cachefiles.h b/include/trace/events/cachefiles.h
index 093c4ac..c6f5aa7 100644 (file)
--- a/include/trace/events/cachefiles.h
+++ b/include/trace/events/cachefiles.h
@@ -573,6 +573,27 @@ TRACE_EVENT(cachefiles_mark_active,
                      __entry->obj, __entry->inode)
            );
 
+TRACE_EVENT(cachefiles_mark_failed,
+           TP_PROTO(struct cachefiles_object *obj,
+                    struct inode *inode),
+
+           TP_ARGS(obj, inode),
+
+           /* Note that obj may be NULL */
+           TP_STRUCT__entry(
+                   __field(unsigned int,               obj             )
+                   __field(ino_t,                      inode           )
+                            ),
+
+           TP_fast_assign(
+                   __entry->obj        = obj ? obj->debug_id : 0;
+                   __entry->inode      = inode->i_ino;
+                          ),
+
+           TP_printk("o=%08x B=%lx",
+                     __entry->obj, __entry->inode)
+           );
+
 TRACE_EVENT(cachefiles_mark_inactive,
            TP_PROTO(struct cachefiles_object *obj,
                     struct inode *inode),