diff mbox

Btrfs: don't delete csum for free space cache

Message ID 1418418042-1105-1-git-send-email-jbacik@fb.com (mailing list archive)
State Rejected
Headers show

Commit Message

Josef Bacik Dec. 12, 2014, 9 p.m. UTC 
We unconditionally delete csums for data extents, but we don't have csums for
free space cache, so all this does is force us to recow the csum root, which
will cause us to re-write the block group cache.  This patch fixes this by
noticing if we're a free space cache extent and simply skipping the delete csum
step.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fb.com>
---
 fs/btrfs/delayed-ref.c | 8 ++++++++
 fs/btrfs/delayed-ref.h | 1 +
 fs/btrfs/extent-tree.c | 8 ++++++--
 3 files changed, 15 insertions(+), 2 deletions(-)

Comments

Josef Bacik Dec. 16, 2014, 8:16 p.m. UTC | #1 
On 12/12/2014 04:00 PM, Josef Bacik wrote:
> We unconditionally delete csums for data extents, but we don't have csums for
> free space cache, so all this does is force us to recow the csum root, which
> will cause us to re-write the block group cache.  This patch fixes this by
> noticing if we're a free space cache extent and simply skipping the delete csum
> step.  Thanks,
>

I'm axe'ing this patch.  Thanks,

Josef

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diff mbox

Patch

diff --git a/fs/btrfs/delayed-ref.c b/fs/btrfs/delayed-ref.c
index 6d16bea..7c729c3 100644
--- a/fs/btrfs/delayed-ref.c
+++ b/fs/btrfs/delayed-ref.c
@@ -605,6 +605,7 @@  add_delayed_ref_head(struct btrfs_fs_info *fs_info,
 	head_ref->is_data = is_data;
 	head_ref->ref_root = RB_ROOT;
 	head_ref->processing = 0;
+	head_ref->no_csums = 0;
 
 	spin_lock_init(&head_ref->lock);
 	mutex_init(&head_ref->mutex);
@@ -848,6 +849,13 @@  int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info,
 	head_ref = add_delayed_ref_head(fs_info, trans, &head_ref->node,
 					bytenr, num_bytes, action, 1);
 
+	/*
+	 * If ref_root is the tree root then this is a block group space cache
+	 * extent and doesn't have csums, so we can set no_csums.
+	 */
+	if (ref_root == BTRFS_ROOT_TREE_OBJECTID)
+		head_ref->no_csums = 1;
+
 	add_delayed_data_ref(fs_info, trans, head_ref, &ref->node, bytenr,
 				   num_bytes, parent, ref_root, owner, offset,
 				   action, no_quota);
diff --git a/fs/btrfs/delayed-ref.h b/fs/btrfs/delayed-ref.h
index a764e23..c464dd3 100644
--- a/fs/btrfs/delayed-ref.h
+++ b/fs/btrfs/delayed-ref.h
@@ -101,6 +101,7 @@  struct btrfs_delayed_ref_head {
 	 * the free has happened.
 	 */
 	unsigned int must_insert_reserved:1;
+	unsigned int no_csums:1;
 	unsigned int is_data:1;
 	unsigned int processing:1;
 };
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 74eb29d..23b704e 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2312,7 +2312,7 @@  static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
 		if (insert_reserved) {
 			btrfs_pin_extent(root, node->bytenr,
 					 node->num_bytes, 1);
-			if (head->is_data) {
+			if (head->is_data && !head->no_csums) {
 				ret = btrfs_del_csums(trans, root,
 						      node->bytenr,
 						      node->num_bytes);
@@ -6094,7 +6094,11 @@  static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
 		}
 		btrfs_release_path(path);
 
-		if (is_data) {
+		/*
+		 * If the ref root is the tree root then this is a nodatasum
+		 * extent and we can skip the btrfs_del_csums step.
+		 */
+		if (is_data && (root_objectid != BTRFS_ROOT_TREE_OBJECTID)) {
 			ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
 			if (ret) {
 				btrfs_abort_transaction(trans, extent_root, ret);