btrfs: abort transaction on specific error places when walking log tree

[ Upstream commit 6ebd726b ]

We do several things while walking a log tree (for replaying and for
freeing a log tree) like reading extent buffers and cleaning them up,
but we don't immediately abort the transaction, or turn the fs into an
error state, when one of these things fails. Instead we the transaction
abort or turn the fs into error state in the caller of the entry point
function that walks a log tree - walk_log_tree() - which means we don't
get to know exactly where an error came from.

Improve on this by doing a transaction abort / turn fs into error state
after each such failure so that when it happens we have a better
understanding where the failure comes from. This deliberately leaves
the transaction abort / turn fs into error state in the callers of
walk_log_tree() as to ensure we don't get into an inconsistent state in
case we forget to do it deeper in call chain. It also deliberately does
not do it after errors from the calls to the callback defined in
struct walk_control::process_func(), as we will do it later on another
patch.

Reviewed-by: Boris Burkov <boris@bur.io>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>