[v9,40/41] btrfs: reorder log node allocation

Commit Message

Naohiro Aota Oct. 30, 2020, 1:51 p.m. UTC

This is the 3/3 patch to enable tree-log on ZONED mode.

The allocation order of nodes of "fs_info->log_root_tree" and nodes of
"root->log_root" is not the same as the writing order of them. So, the
writing causes unaligned write errors.

This patch reorders the allocation of them by delaying allocation of the
root node of "fs_info->log_root_tree," so that the node buffers can go out
sequentially to devices.

Signed-off-by: Johannes Thumshirn <[e-mail]>
Signed-off-by: Naohiro Aota <[e-mail]>
---
 fs/btrfs/disk-io.c  |  6 ------
 fs/btrfs/tree-log.c | 24 ++++++++++++++++++------
 2 files changed, 18 insertions(+), 12 deletions(-)

Comments

Josef Bacik Nov. 3, 2020, 8:49 p.m. UTC | #1

On 10/30/20 9:51 AM, Naohiro Aota wrote:
> This is the 3/3 patch to enable tree-log on ZONED mode.
> 
> The allocation order of nodes of "fs_info->log_root_tree" and nodes of
> "root->log_root" is not the same as the writing order of them. So, the
> writing causes unaligned write errors.
> 
> This patch reorders the allocation of them by delaying allocation of the
> root node of "fs_info->log_root_tree," so that the node buffers can go out
> sequentially to devices.
> 
> Signed-off-by: Johannes Thumshirn <[e-mail]>
> Signed-off-by: Naohiro Aota <[e-mail]>

If you keep the tree log stuff, you can add

Reviewed-by: Josef Bacik <[e-mail]>

Thanks,

Josef

Patch

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 70885f3d3321..2c2fa5ebfef1 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1255,16 +1255,10 @@  int btrfs_init_log_root_tree(struct btrfs_trans_handle *trans,
 			     struct btrfs_fs_info *fs_info)
 {
 	struct btrfs_root *log_root;
-	int ret;
 
 	log_root = alloc_log_tree(trans, fs_info);
 	if (IS_ERR(log_root))
 		return PTR_ERR(log_root);
-	ret = btrfs_alloc_log_tree_node(trans, log_root);
-	if (ret) {
-		kfree(log_root);
-		return ret;
-	}
 	WARN_ON(fs_info->log_root_tree);
 	fs_info->log_root_tree = log_root;
 	return 0;
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 826af2ff4740..46ff92a18474 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -3140,6 +3140,16 @@  int btrfs_sync_log(struct btrfs_trans_handle *trans,
 	list_add_tail(&root_log_ctx.list, &log_root_tree->log_ctxs[index2]);
 	root_log_ctx.log_transid = log_root_tree->log_transid;
 
+	mutex_lock(&fs_info->tree_log_mutex);
+	if (!log_root_tree->node) {
+		ret = btrfs_alloc_log_tree_node(trans, log_root_tree);
+		if (ret) {
+			mutex_unlock(&fs_info->tree_log_mutex);
+			goto out;
+		}
+	}
+	mutex_unlock(&fs_info->tree_log_mutex);
+
 	/*
 	 * Now we are safe to update the log_root_tree because we're under the
 	 * log_mutex, and we're a current writer so we're holding the commit
@@ -3289,12 +3299,14 @@  static void free_log_tree(struct btrfs_trans_handle *trans,
 		.process_func = process_one_buffer
 	};
 
-	ret = walk_log_tree(trans, log, &wc);
-	if (ret) {
-		if (trans)
-			btrfs_abort_transaction(trans, ret);
-		else
-			btrfs_handle_fs_error(log->fs_info, ret, NULL);
+	if (log->node) {
+		ret = walk_log_tree(trans, log, &wc);
+		if (ret) {
+			if (trans)
+				btrfs_abort_transaction(trans, ret);
+			else
+				btrfs_handle_fs_error(log->fs_info, ret, NULL);
+		}
 	}
 
 	clear_extent_bits(&log->dirty_log_pages, 0, (u64)-1,