[PATCH 1/6] btrfs: enable a tracepoint when we fail tickets

[Josef Bacik <josef@toxicpanda.com>]

When debugging early enospc problems it was useful to have a tracepoint
where we failed all tickets so I could check the state of the enospc
counters at failure time to validate my fixes.  This adds the tracpoint
so you can easily get that information.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
 fs/btrfs/space-info.c        | 2 ++
 include/trace/events/btrfs.h | 6 ++++++
 2 files changed, 8 insertions(+)

diff --git a/fs/btrfs/space-info.c b/fs/btrfs/space-info.c
index 392997376a1c..af161eb808a2 100644
--- a/fs/btrfs/space-info.c
+++ b/fs/btrfs/space-info.c
@@ -825,6 +825,8 @@ static bool maybe_fail_all_tickets(struct btrfs_fs_info *fs_info,
 	struct reserve_ticket *ticket;
 	u64 tickets_id = space_info->tickets_id;
 
+	trace_btrfs_fail_all_tickets(fs_info, space_info);
+
 	if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
 		btrfs_info(fs_info, "cannot satisfy tickets, dumping space info");
 		__btrfs_dump_space_info(fs_info, space_info);
diff --git a/include/trace/events/btrfs.h b/include/trace/events/btrfs.h
index c7237317a8b9..3d81ba8c37b9 100644
--- a/include/trace/events/btrfs.h
+++ b/include/trace/events/btrfs.h
@@ -2098,6 +2098,12 @@ DEFINE_EVENT(btrfs_dump_space_info, btrfs_done_preemptive_reclaim,
 	TP_ARGS(fs_info, sinfo)
 );
 
+DEFINE_EVENT(btrfs_dump_space_info, btrfs_fail_all_tickets,
+	TP_PROTO(const struct btrfs_fs_info *fs_info,
+		 const struct btrfs_space_info *sinfo),
+	TP_ARGS(fs_info, sinfo)
+);
+
 TRACE_EVENT(btrfs_reserve_ticket,
 	TP_PROTO(const struct btrfs_fs_info *fs_info, u64 flags, u64 bytes,
 		 u64 start_ns, int flush, int error),
-- 
2.26.3