btrfs: add tracepoints for ordered extents

When debugging a reference counting issue with ordered extents, I've found
we're lacking a lot of tracepoint coverage in the ordered extent code.

Close these gaps by adding tracepoints after every refcount_inc() in the
ordered extent code.

Reviewed-by: Boris Burkov <boris@bur.io>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c
index dc88d2b3721fdfed538a6b3817ab7c42185b662c..41b3bc44c92b233a65c73574e30a9544db6e7eef 100644 (file)
--- a/fs/btrfs/ordered-data.c
+++ b/fs/btrfs/ordered-data.c
@@ -401,6 +401,7 @@ void btrfs_mark_ordered_io_finished(struct btrfs_inode *inode,
                        set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
                        cond_wake_up(&entry->wait);
                        refcount_inc(&entry->refs);
+                       trace_btrfs_ordered_extent_mark_finished(inode, entry);
                        spin_unlock_irqrestore(&tree->lock, flags);
                        btrfs_init_work(&entry->work, finish_func, NULL, NULL);
                        btrfs_queue_work(wq, &entry->work);
@@ -473,6 +474,7 @@ out:
        if (finished && cached && entry) {
                *cached = entry;
                refcount_inc(&entry->refs);
+               trace_btrfs_ordered_extent_dec_test_pending(inode, entry);
        }
        spin_unlock_irqrestore(&tree->lock, flags);
        return finished;
@@ -807,8 +809,10 @@ struct btrfs_ordered_extent *btrfs_lookup_ordered_extent(struct btrfs_inode *ino
        entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
        if (!in_range(file_offset, entry->file_offset, entry->num_bytes))
                entry = NULL;
-       if (entry)
+       if (entry) {
                refcount_inc(&entry->refs);
+               trace_btrfs_ordered_extent_lookup(inode, entry);
+       }
 out:
        spin_unlock_irqrestore(&tree->lock, flags);
        return entry;
@@ -848,8 +852,10 @@ struct btrfs_ordered_extent *btrfs_lookup_ordered_range(
                        break;
        }
 out:
-       if (entry)
+       if (entry) {
                refcount_inc(&entry->refs);
+               trace_btrfs_ordered_extent_lookup_range(inode, entry);
+       }
        spin_unlock_irq(&tree->lock);
        return entry;
 }
@@ -878,6 +884,7 @@ void btrfs_get_ordered_extents_for_logging(struct btrfs_inode *inode,
                ASSERT(list_empty(&ordered->log_list));
                list_add_tail(&ordered->log_list, list);
                refcount_inc(&ordered->refs);
+               trace_btrfs_ordered_extent_lookup_for_logging(inode, ordered);
        }
        spin_unlock_irq(&tree->lock);
 }
@@ -901,6 +908,7 @@ btrfs_lookup_first_ordered_extent(struct btrfs_inode *inode, u64 file_offset)
 
        entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
        refcount_inc(&entry->refs);
+       trace_btrfs_ordered_extent_lookup_first(inode, entry);
 out:
        spin_unlock_irq(&tree->lock);
        return entry;
@@ -975,8 +983,11 @@ struct btrfs_ordered_extent *btrfs_lookup_first_ordered_range(
        /* No ordered extent in the range */
        entry = NULL;
 out:
-       if (entry)
+       if (entry) {
                refcount_inc(&entry->refs);
+               trace_btrfs_ordered_extent_lookup_first_range(inode, entry);
+       }
+
        spin_unlock_irq(&tree->lock);
        return entry;
 }
@@ -1055,6 +1066,8 @@ int btrfs_split_ordered_extent(struct btrfs_ordered_extent *ordered, u64 pre,
        struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
        int ret = 0;
 
+       trace_btrfs_ordered_extent_split(BTRFS_I(inode), ordered);
+
        spin_lock_irq(&tree->lock);
        /* Remove from tree once */
        node = &ordered->rb_node;

diff --git a/include/trace/events/btrfs.h b/include/trace/events/btrfs.h
index 29fa8ea2cc0f6c8a1883e719111a0026f04d1911..73df80d462dc83ef760270988d71553931418da2 100644 (file)
--- a/include/trace/events/btrfs.h
+++ b/include/trace/events/btrfs.h
@@ -598,6 +598,70 @@ DEFINE_EVENT(btrfs__ordered_extent, btrfs_ordered_extent_put,
        TP_ARGS(inode, ordered)
 );
 
+DEFINE_EVENT(btrfs__ordered_extent, btrfs_ordered_extent_lookup,
+
+            TP_PROTO(const struct btrfs_inode *inode,
+                     const struct btrfs_ordered_extent *ordered),
+
+            TP_ARGS(inode, ordered)
+);
+
+DEFINE_EVENT(btrfs__ordered_extent, btrfs_ordered_extent_lookup_range,
+
+            TP_PROTO(const struct btrfs_inode *inode,
+                     const struct btrfs_ordered_extent *ordered),
+
+            TP_ARGS(inode, ordered)
+);
+
+DEFINE_EVENT(btrfs__ordered_extent, btrfs_ordered_extent_lookup_first_range,
+
+            TP_PROTO(const struct btrfs_inode *inode,
+                     const struct btrfs_ordered_extent *ordered),
+
+            TP_ARGS(inode, ordered)
+);
+
+DEFINE_EVENT(btrfs__ordered_extent, btrfs_ordered_extent_lookup_for_logging,
+
+            TP_PROTO(const struct btrfs_inode *inode,
+                     const struct btrfs_ordered_extent *ordered),
+
+            TP_ARGS(inode, ordered)
+);
+
+DEFINE_EVENT(btrfs__ordered_extent, btrfs_ordered_extent_lookup_first,
+
+            TP_PROTO(const struct btrfs_inode *inode,
+                     const struct btrfs_ordered_extent *ordered),
+
+            TP_ARGS(inode, ordered)
+);
+
+DEFINE_EVENT(btrfs__ordered_extent, btrfs_ordered_extent_split,
+
+            TP_PROTO(const struct btrfs_inode *inode,
+                     const struct btrfs_ordered_extent *ordered),
+
+            TP_ARGS(inode, ordered)
+);
+
+DEFINE_EVENT(btrfs__ordered_extent, btrfs_ordered_extent_dec_test_pending,
+
+            TP_PROTO(const struct btrfs_inode *inode,
+                     const struct btrfs_ordered_extent *ordered),
+
+            TP_ARGS(inode, ordered)
+);
+
+DEFINE_EVENT(btrfs__ordered_extent, btrfs_ordered_extent_mark_finished,
+
+            TP_PROTO(const struct btrfs_inode *inode,
+                     const struct btrfs_ordered_extent *ordered),
+
+            TP_ARGS(inode, ordered)
+);
+
 DECLARE_EVENT_CLASS(btrfs__writepage,
 
        TP_PROTO(const struct page *page, const struct inode *inode,