From: Josef Bacik josef@toxicpanda.com
[ Upstream commit 50dbbb71c79df89532ec41d118d59386e5a877e3 ]
There are two bugs here, but fixing them independently would just result in pain if you happened to bisect between the two patches.
First is how we handle the -EAGAIN from relocate_tree_block(). We don't set error, unless we happen to be the first node, which makes no sense, I have no idea what the code was trying to accomplish here.
We in fact _do_ want err set here so that we know we need to restart in relocate_block_group(). Also we need finish_pending_nodes() to not actually call link_to_upper(), because we didn't actually relocate the block.
And then if we do get -EAGAIN we do not want to set our backref cache last_trans to the one before ours. This would force us to update our backref cache if we didn't cross transaction ids, which would mean we'd have some nodes updated to their new_bytenr, but still able to find their old bytenr because we're searching the same commit root as the last time we went through relocate_tree_blocks.
Fixing these two things keeps us from panicing when we start breaking out of relocate_tree_blocks() either for delayed ref flushing or enospc.
Signed-off-by: Josef Bacik josef@toxicpanda.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/btrfs/relocation.c | 11 ++--------- 1 file changed, 2 insertions(+), 9 deletions(-)
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c index e1337598d15ea..e3ba1c12008a9 100644 --- a/fs/btrfs/relocation.c +++ b/fs/btrfs/relocation.c @@ -3176,9 +3176,8 @@ int relocate_tree_blocks(struct btrfs_trans_handle *trans, ret = relocate_tree_block(trans, rc, node, &block->key, path); if (ret < 0) { - if (ret != -EAGAIN || &block->rb_node == rb_first(blocks)) - err = ret; - goto out; + err = ret; + break; } } out: @@ -4154,12 +4153,6 @@ static noinline_for_stack int relocate_block_group(struct reloc_control *rc) if (!RB_EMPTY_ROOT(&blocks)) { ret = relocate_tree_blocks(trans, rc, &blocks); if (ret < 0) { - /* - * if we fail to relocate tree blocks, force to update - * backref cache when committing transaction. - */ - rc->backref_cache.last_trans = trans->transid - 1; - if (ret != -EAGAIN) { err = ret; break;