David, could you fold the below incremental diff to this patch? Or, I can send a full replacement patch.
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c index 8be3164d4c5d..4e72794342c0 100644 --- a/fs/btrfs/tree-log.c +++ b/fs/btrfs/tree-log.c @@ -143,6 +143,7 @@ static int start_log_trans(struct btrfs_trans_handle *trans, struct btrfs_root *tree_root = fs_info->tree_root; const bool zoned = btrfs_is_zoned(fs_info); int ret = 0; + bool created = false; /* * First check if the log root tree was already created. If not, create @@ -152,8 +153,10 @@ static int start_log_trans(struct btrfs_trans_handle *trans, mutex_lock(&tree_root->log_mutex); if (!fs_info->log_root_tree) { ret = btrfs_init_log_root_tree(trans, fs_info); - if (!ret) + if (!ret) { set_bit(BTRFS_ROOT_HAS_LOG_TREE, &tree_root->state); + created = true; + } } mutex_unlock(&tree_root->log_mutex); if (ret) @@ -183,16 +186,16 @@ static int start_log_trans(struct btrfs_trans_handle *trans, set_bit(BTRFS_ROOT_MULTI_LOG_TASKS, &root->state); } } else { - if (zoned) { - mutex_lock(&fs_info->tree_log_mutex); - if (fs_info->log_root_tree) - ret = -EAGAIN; - else - ret = btrfs_init_log_root_tree(trans, fs_info); - mutex_unlock(&fs_info->tree_log_mutex); - } - if (ret) + /* + * This means fs_info->log_root_tree was already created + * for some other FS trees. Do the full commit not to mix + * nodes from multiple log transactions to do sequential + * writing. + */ + if (zoned && !created) { + ret = -EAGAIN; goto out; + } ret = btrfs_add_log_tree(trans, root); if (ret) On Thu, Feb 04, 2021 at 07:22:19PM +0900, Naohiro Aota wrote: > This is the 2/3 patch to enable tree-log on zoned filesystems. > > Since we can start more than one log transactions per subvolume > simultaneously, nodes from multiple transactions can be allocated > interleaved. Such mixed allocation results in non-sequential writes at the > time of a log transaction commit. The nodes of the global log root tree > (fs_info->log_root_tree), also have the same problem with mixed > allocation. > > Serializes log transactions by waiting for a committing transaction when > someone tries to start a new transaction, to avoid the mixed allocation > problem. We must also wait for running log transactions from another > subvolume, but there is no easy way to detect which subvolume root is > running a log transaction. So, this patch forbids starting a new log > transaction when other subvolumes already allocated the global log root > tree. > > Cc: Filipe Manana <fdman...@gmail.com> > Reviewed-by: Josef Bacik <jo...@toxicpanda.com> > Signed-off-by: Naohiro Aota <naohiro.a...@wdc.com> > --- > fs/btrfs/tree-log.c | 29 +++++++++++++++++++++++++++++ > 1 file changed, 29 insertions(+) > > diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c > index c02eeeac439c..8be3164d4c5d 100644 > --- a/fs/btrfs/tree-log.c > +++ b/fs/btrfs/tree-log.c > @@ -105,6 +105,7 @@ static noinline int replay_dir_deletes(struct > btrfs_trans_handle *trans, > struct btrfs_root *log, > struct btrfs_path *path, > u64 dirid, int del_all); > +static void wait_log_commit(struct btrfs_root *root, int transid); > > /* > * tree logging is a special write ahead log used to make sure that > @@ -140,6 +141,7 @@ static int start_log_trans(struct btrfs_trans_handle > *trans, > { > struct btrfs_fs_info *fs_info = root->fs_info; > struct btrfs_root *tree_root = fs_info->tree_root; > + const bool zoned = btrfs_is_zoned(fs_info); > int ret = 0; > > /* > @@ -160,12 +162,20 @@ static int start_log_trans(struct btrfs_trans_handle > *trans, > > mutex_lock(&root->log_mutex); > > +again: > if (root->log_root) { > + int index = (root->log_transid + 1) % 2; > + > if (btrfs_need_log_full_commit(trans)) { > ret = -EAGAIN; > goto out; > } > > + if (zoned && atomic_read(&root->log_commit[index])) { > + wait_log_commit(root, root->log_transid - 1); > + goto again; > + } > + > if (!root->log_start_pid) { > clear_bit(BTRFS_ROOT_MULTI_LOG_TASKS, &root->state); > root->log_start_pid = current->pid; > @@ -173,6 +183,17 @@ static int start_log_trans(struct btrfs_trans_handle > *trans, > set_bit(BTRFS_ROOT_MULTI_LOG_TASKS, &root->state); > } > } else { > + if (zoned) { > + mutex_lock(&fs_info->tree_log_mutex); > + if (fs_info->log_root_tree) > + ret = -EAGAIN; > + else > + ret = btrfs_init_log_root_tree(trans, fs_info); > + mutex_unlock(&fs_info->tree_log_mutex); > + } > + if (ret) > + goto out; > + > ret = btrfs_add_log_tree(trans, root); > if (ret) > goto out; > @@ -201,14 +222,22 @@ static int start_log_trans(struct btrfs_trans_handle > *trans, > */ > static int join_running_log_trans(struct btrfs_root *root) > { > + const bool zoned = btrfs_is_zoned(root->fs_info); > int ret = -ENOENT; > > if (!test_bit(BTRFS_ROOT_HAS_LOG_TREE, &root->state)) > return ret; > > mutex_lock(&root->log_mutex); > +again: > if (root->log_root) { > + int index = (root->log_transid + 1) % 2; > + > ret = 0; > + if (zoned && atomic_read(&root->log_commit[index])) { > + wait_log_commit(root, root->log_transid - 1); > + goto again; > + } > atomic_inc(&root->log_writers); > } > mutex_unlock(&root->log_mutex); > -- > 2.30.0 >