btrfs: simplify error handling of clean_pinned_extents()

At clean_pinned_extents(), whether we end up returning success or failure,
we pretty much have to do the same things:

1) unlock unused_bg_unpin_mutex
2) decrement reference count on the previous transaction

We also call btrfs_dec_block_group_ro() in case of failure, but that is
better done in its caller, btrfs_delete_unused_bgs(), since its the
caller that calls inc_block_group_ro(), so it should be responsible for
the decrement operation, as it is in case any of the other functions it
calls fail.

So move the call to btrfs_dec_block_group_ro() from clean_pinned_extents()
into  btrfs_delete_unused_bgs() and unify the error and success return
paths for clean_pinned_extents(), reducing duplicated code and making it
simpler.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c
index 233c566..5627f53 100644 (file)
--- a/fs/btrfs/block-group.c
+++ b/fs/btrfs/block-group.c
@@ -1284,25 +1284,17 @@ static bool clean_pinned_extents(struct btrfs_trans_handle *trans,
                ret = clear_extent_bits(&prev_trans->pinned_extents, start, end,
                                        EXTENT_DIRTY);
                if (ret)
-                       goto err;
+                       goto out;
        }
 
        ret = clear_extent_bits(&trans->transaction->pinned_extents, start, end,
                                EXTENT_DIRTY);
-       if (ret)
-               goto err;
+out:
        mutex_unlock(&fs_info->unused_bg_unpin_mutex);
        if (prev_trans)
                btrfs_put_transaction(prev_trans);
 
-       return true;
-
-err:
-       mutex_unlock(&fs_info->unused_bg_unpin_mutex);
-       if (prev_trans)
-               btrfs_put_transaction(prev_trans);
-       btrfs_dec_block_group_ro(bg);
-       return false;
+       return ret == 0;
 }
 
 /*
@@ -1400,8 +1392,10 @@ void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
                 * We could have pending pinned extents for this block group,
                 * just delete them, we don't care about them anymore.
                 */
-               if (!clean_pinned_extents(trans, block_group))
+               if (!clean_pinned_extents(trans, block_group)) {
+                       btrfs_dec_block_group_ro(block_group);
                        goto end_trans;
+               }
 
                /*
                 * At this point, the block_group is read only and should fail