btrfs: add a node counter to each of the rbtrees

This patch adds counters to each of the rbtrees so that we can tell
how large they are growing for a given workload.  These counters
will be exported by tracepoints in the next patch.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index baf907adede1..297f33850425 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -136,9 +136,10 @@ struct prelim_ref {
 
 struct preftree {
         struct rb_root root;
+        unsigned int count;
 };
 
-#define PREFTREE_INIT   { .root = RB_ROOT }
+#define PREFTREE_INIT   { .root = RB_ROOT, .count = 0 }
 
 struct preftrees {
         struct preftree direct;    /* BTRFS_SHARED_[DATA|BLOCK]_REF_KEY */
@@ -248,6 +249,7 @@ static void prelim_ref_insert(struct preftree *preftree,
                 }
         }
 
+        preftree->count++;
         rb_link_node(&newref->rbnode, parent, p);
         rb_insert_color(&newref->rbnode, root);
 }
@@ -265,6 +267,7 @@ static void prelim_release(struct preftree *preftree)
                 free_pref(ref);
 
         preftree->root = RB_ROOT;
+        preftree->count = 0;
 }
 
 /*
@@ -608,6 +611,7 @@ static int resolve_indirect_refs(struct btrfs_fs_info *fs_info,
                 }
 
                 rb_erase(&ref->rbnode, &preftrees->indirect.root);
+                preftrees->indirect.count--;
 
                 if (ref->count == 0) {
                         free_pref(ref);