locks: prink more detail when there are leaked locks

Right now, we just get WARN_ON_ONCE, which is not particularly helpful.
Have it dump some info about the locks and the inode to make it easier
to track down leaked locks in the future.

Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Acked-by: "J. Bruce Fields" <bfields@fieldses.org>

diff --git a/fs/locks.c b/fs/locks.c
index ed9ab93..ca272eb 100644 (file)
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -233,15 +233,40 @@ out:
        return ctx;
 }
 
+static void
+locks_dump_ctx_list(struct list_head *list, char *list_type)
+{
+       struct file_lock *fl;
+
+       list_for_each_entry(fl, list, fl_list) {
+               pr_warn("%s: fl_owner=%p fl_flags=0x%x fl_type=0x%x fl_pid=%u\n", list_type, fl->fl_owner, fl->fl_flags, fl->fl_type, fl->fl_pid);
+       }
+}
+
+static void
+locks_check_ctx_lists(struct inode *inode)
+{
+       struct file_lock_context *ctx = inode->i_flctx;
+
+       if (unlikely(!list_empty(&ctx->flc_flock) ||
+                    !list_empty(&ctx->flc_posix) ||
+                    !list_empty(&ctx->flc_lease))) {
+               pr_warn("Leaked locks on dev=0x%x:0x%x ino=0x%lx:\n",
+                       MAJOR(inode->i_sb->s_dev), MINOR(inode->i_sb->s_dev),
+                       inode->i_ino);
+               locks_dump_ctx_list(&ctx->flc_flock, "FLOCK");
+               locks_dump_ctx_list(&ctx->flc_posix, "POSIX");
+               locks_dump_ctx_list(&ctx->flc_lease, "LEASE");
+       }
+}
+
 void
 locks_free_lock_context(struct inode *inode)
 {
        struct file_lock_context *ctx = inode->i_flctx;
 
-       if (ctx) {
-               WARN_ON_ONCE(!list_empty(&ctx->flc_flock));
-               WARN_ON_ONCE(!list_empty(&ctx->flc_posix));
-               WARN_ON_ONCE(!list_empty(&ctx->flc_lease));
+       if (unlikely(ctx)) {
+               locks_check_ctx_lists(inode);
                kmem_cache_free(flctx_cache, ctx);
        }
 }