| From 7fb7d76f96bfcbea25007d190ba828b18e13d29d Mon Sep 17 00:00:00 2001 |
| From: Josef Bacik <jbacik@fusionio.com> |
| 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 |
| |
| From: Josef Bacik <jbacik@fusionio.com> |
| |
| 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 <list.btrfs@jan-o-sch.net> |
| Signed-off-by: Josef Bacik <jbacik@fusionio.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| fs/btrfs/ctree.c | 3 ++- |
| 1 file changed, 2 insertions(+), 1 deletion(-) |
| |
| --- a/fs/btrfs/ctree.c |
| +++ b/fs/btrfs/ctree.c |
| @@ -1049,7 +1049,8 @@ static noinline int __btrfs_cow_block(st |
| 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); |
| } |
