From 8fdbfe8d1690e8a38d497d83a30607d0d90cc15a Mon Sep 17 00:00:00 2001 From: Nikos Tsironis Date: Wed, 4 Dec 2019 16:06:53 +0200 Subject: dm clone metadata: Use a two phase commit Split the metadata commit in two parts: 1. dm_clone_metadata_pre_commit(): Prepare the current transaction for committing. After this is called, all subsequent metadata updates, done through either dm_clone_set_region_hydrated() or dm_clone_cond_set_range(), will be part of the next transaction. 2. dm_clone_metadata_commit(): Actually commit the current transaction to disk and start a new transaction. This is required by the following commit. It allows dm-clone to flush the destination device after step (1) to ensure that all freshly hydrated regions, for which we are updating the metadata, are properly written to non-volatile storage and won't be lost in case of a crash. Fixes: 7431b7835f55 ("dm: add clone target") Cc: stable@vger.kernel.org # v5.4+ Signed-off-by: Nikos Tsironis Signed-off-by: Mike Snitzer --- drivers/md/dm-clone-target.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'drivers/md/dm-clone-target.c') diff --git a/drivers/md/dm-clone-target.c b/drivers/md/dm-clone-target.c index b3d89072d21c..613c913c296c 100644 --- a/drivers/md/dm-clone-target.c +++ b/drivers/md/dm-clone-target.c @@ -1122,8 +1122,13 @@ static int commit_metadata(struct clone *clone) goto out; } - r = dm_clone_metadata_commit(clone->cmd); + r = dm_clone_metadata_pre_commit(clone->cmd); + if (unlikely(r)) { + __metadata_operation_failed(clone, "dm_clone_metadata_pre_commit", r); + goto out; + } + r = dm_clone_metadata_commit(clone->cmd); if (unlikely(r)) { __metadata_operation_failed(clone, "dm_clone_metadata_commit", r); goto out; -- cgit v1.2.3