btrfs: tracepoints: add trace event for log_new_delayed_dentries()

log_new_delayed_dentries() is an important step called during a fsync, as
well as during rename and link operations on inodes that were previously
logged. Add trace events for when entering and exiting that function.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 12421ae640be5fc1a6a24cb51f2b2ef8fa2fa4e0..2ed15485fe5a593d9d2498ccd1e7bad631e435f7 100644 (file)
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -6844,6 +6844,15 @@ static int log_new_delayed_dentries(struct btrfs_trans_handle *trans,
        lockdep_assert_not_held(&inode->log_mutex);
 
        ASSERT(!ctx->logging_new_delayed_dentries);
+
+       /*
+        * Return early if empty list, avoid emitting redundant trace events
+        * that generate noise only.
+        */
+       if (list_empty(delayed_ins_list))
+               return 0;
+
+       trace_btrfs_log_new_delayed_dentries_enter(trans, inode);
        ctx->logging_new_delayed_dentries = true;
 
        list_for_each_entry(item, delayed_ins_list, log_list) {
@@ -6886,6 +6895,7 @@ static int log_new_delayed_dentries(struct btrfs_trans_handle *trans,
 
        ctx->log_new_dentries = orig_log_new_dentries;
        ctx->logging_new_delayed_dentries = false;
+       trace_btrfs_log_new_delayed_dentries_exit(trans, inode, ret);
 
        return ret;
 }

diff --git a/include/trace/events/btrfs.h b/include/trace/events/btrfs.h
index 2eff817026a4c2de87bb04780844e1d76e87e19d..dd7731b484aafd031cc1818ab430caeac5d966bc 100644 (file)
--- a/include/trace/events/btrfs.h
+++ b/include/trace/events/btrfs.h
@@ -1347,6 +1347,59 @@ TRACE_EVENT(btrfs_log_conflicting_inodes_exit,
                        __entry->ctx_ino, __entry->ret)
 );
 
+TRACE_EVENT(btrfs_log_new_delayed_dentries_enter,
+
+       TP_PROTO(const struct btrfs_trans_handle *trans,
+                const struct btrfs_inode *inode),
+
+       TP_ARGS(trans, inode),
+
+       TP_STRUCT__entry_btrfs(
+               __field(        u64,            root_objectid           )
+               __field(        u64,            transid                 )
+               __field(        u64,            ino                     )
+       ),
+
+       TP_fast_assign(
+               TP_fast_assign_fsid(trans->fs_info);
+               __entry->root_objectid          = btrfs_root_id(inode->root);
+               __entry->transid                = trans->transid;
+               __entry->ino                    = btrfs_ino(inode);
+       ),
+
+       TP_printk_btrfs("root=%llu(%s) transid=%llu ino=%llu",
+                       show_root_type(__entry->root_objectid), __entry->transid,
+                       __entry->ino)
+);
+
+TRACE_EVENT(btrfs_log_new_delayed_dentries_exit,
+
+       TP_PROTO(const struct btrfs_trans_handle *trans,
+                const struct btrfs_inode *inode,
+                int ret),
+
+       TP_ARGS(trans, inode, ret),
+
+       TP_STRUCT__entry_btrfs(
+               __field(        u64,            root_objectid           )
+               __field(        u64,            transid                 )
+               __field(        u64,            ino                     )
+               __field(        int,            ret                     )
+       ),
+
+       TP_fast_assign(
+               TP_fast_assign_fsid(trans->fs_info);
+               __entry->root_objectid          = btrfs_root_id(inode->root);
+               __entry->transid                = trans->transid;
+               __entry->ino                    = btrfs_ino(inode);
+               __entry->ret                    = ret;
+       ),
+
+       TP_printk_btrfs("root=%llu(%s) transid=%llu ino=%llu ret=%d",
+                       show_root_type(__entry->root_objectid), __entry->transid,
+                       __entry->ino, __entry->ret)
+);
+
 TRACE_EVENT(btrfs_sync_fs,
 
        TP_PROTO(const struct btrfs_fs_info *fs_info, int wait),