From da94067deee6e073129061575d1a3e437232a6c5 Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Mon, 1 Jul 2013 16:10:16 -0400 Subject: Btrfs: only do the tree_mod_log_free_eb if this is our last ref commit 7fb7d76f96bfcbea25007d190ba828b18e13d29d upstream. There is another bug in the tree mod log stuff in that we're calling tree_mod_log_free_eb every single time a block is cow'ed. The problem with this is that if this block is shared by multiple snapshots we will call this multiple times per block, so if we go to rewind the mod log for this block we'll BUG_ON() in __tree_mod_log_rewind because we try to rewind a free twice. We only want to call tree_mod_log_free_eb if we are actually freeing the block. With this patch I no longer hit the panic in __tree_mod_log_rewind. Thanks, Reviewed-by: Jan Schmidt Signed-off-by: Josef Bacik Signed-off-by: Greg Kroah-Hartman --- fs/btrfs/ctree.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index ca9d8f1a3bb6..7a983f7e6b87 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -1049,7 +1049,8 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans, btrfs_set_node_ptr_generation(parent, parent_slot, trans->transid); btrfs_mark_buffer_dirty(parent); - tree_mod_log_free_eb(root->fs_info, buf); + if (last_ref) + tree_mod_log_free_eb(root->fs_info, buf); btrfs_free_tree_block(trans, root, buf, parent_start, last_ref); } -- cgit v1.2.3