From 393da91819e35af538ef97c7c6a04899e2fbfe0e Mon Sep 17 00:00:00 2001 From: Liu Bo Date: Fri, 5 Jan 2018 12:51:16 -0700 Subject: [PATCH] Btrfs: add tracepoint for em's EEXIST case This is adding a tracepoint 'btrfs_handle_em_exist' to help debug the subtle bugs around merge_extent_mapping. Signed-off-by: Liu Bo Reviewed-by: Josef Bacik Signed-off-by: David Sterba --- fs/btrfs/extent_map.c | 3 +++ include/trace/events/btrfs.h | 35 +++++++++++++++++++++++++++++++++++ 2 files changed, 38 insertions(+) diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c index c80dea7..b8ead8d 100644 --- a/fs/btrfs/extent_map.c +++ b/fs/btrfs/extent_map.c @@ -551,6 +551,9 @@ int btrfs_add_extent_mapping(struct extent_map_tree *em_tree, ret = 0; existing = search_extent_mapping(em_tree, start, len); + + trace_btrfs_handle_em_exist(existing, em, start, len); + /* * existing will always be non-NULL, since there must be * extent causing the -EEXIST. diff --git a/include/trace/events/btrfs.h b/include/trace/events/btrfs.h index c3ac5ec..486771e 100644 --- a/include/trace/events/btrfs.h +++ b/include/trace/events/btrfs.h @@ -248,6 +248,41 @@ TRACE_EVENT_CONDITION(btrfs_get_extent, __entry->refs, __entry->compress_type) ); +TRACE_EVENT(btrfs_handle_em_exist, + + TP_PROTO(const struct extent_map *existing, const struct extent_map *map, u64 start, u64 len), + + TP_ARGS(existing, map, start, len), + + TP_STRUCT__entry( + __field( u64, e_start ) + __field( u64, e_len ) + __field( u64, map_start ) + __field( u64, map_len ) + __field( u64, start ) + __field( u64, len ) + ), + + TP_fast_assign( + __entry->e_start = existing->start; + __entry->e_len = existing->len; + __entry->map_start = map->start; + __entry->map_len = map->len; + __entry->start = start; + __entry->len = len; + ), + + TP_printk("start=%llu len=%llu " + "existing(start=%llu len=%llu) " + "em(start=%llu len=%llu)", + (unsigned long long)__entry->start, + (unsigned long long)__entry->len, + (unsigned long long)__entry->e_start, + (unsigned long long)__entry->e_len, + (unsigned long long)__entry->map_start, + (unsigned long long)__entry->map_len) +); + /* file extent item */ DECLARE_EVENT_CLASS(btrfs__file_extent_item_regular, -- 2.7.4