btrfs: add tracing for failed reservations

When debugging ENOSPC issues, it's nice to be able to see which
reservations failed as well as the ones which succeeded.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 4062a65f9fb7..a807acc9a63e 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -3684,6 +3684,9 @@ commit_trans:
                         goto again;
                 }
 
+                trace_btrfs_space_reservation(root->fs_info,
+                                              "space_info:enospc",
+                                              data_sinfo->flags, bytes, 1);
                 return -ENOSPC;
         }
         data_sinfo->bytes_may_use += bytes;
@@ -4335,6 +4338,10 @@ out:
                     !block_rsv_use_bytes(global_rsv, orig_bytes))
                         ret = 0;
         }
+        if (ret == -ENOSPC)
+                trace_btrfs_space_reservation(root->fs_info,
+                                              "space_info:enospc",
+                                              space_info->flags, orig_bytes, 1);
         if (flushing) {
                 spin_lock(&space_info->lock);
                 space_info->flush = 0;