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authorNikolay Borisov <nborisov@suse.com>2018-08-15 10:39:55 +0300
committerDavid Sterba <dsterba@suse.com>2018-10-15 17:23:35 +0200
commite726138676f896146a55a98305665e81d34d038c (patch)
tree2d6b061c0b7d45ba69527bc68dd874a4f3502646
parentb1cdbcb53a6edd84d50b72117d49a350575bbe6a (diff)
btrfs: Factor out loop processing all refs of a head
This patch introduces a new helper encompassing the implicit inner loop in __btrfs_run_delayed_refs which processes all the refs for a given head. The code is mostly copy/paste, the only difference is that if we detect a newer reference then -EAGAIN is returned so that callers can react correctly. Also, at the end of the loop the head is relocked and btrfs_merge_delayed_refs is run again to retain the pre-refactoring semantics. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
-rw-r--r--fs/btrfs/extent-tree.c77
1 files changed, 77 insertions, 0 deletions
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index ee027a7fe7f4..979702f361cc 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2535,6 +2535,83 @@ static struct btrfs_delayed_ref_head *btrfs_obtain_ref_head(
return head;
}
+static int btrfs_run_delayed_refs_for_head(struct btrfs_trans_handle *trans,
+ struct btrfs_delayed_ref_head *locked_ref,
+ unsigned long *run_refs)
+{
+ struct btrfs_fs_info *fs_info = trans->fs_info;
+ struct btrfs_delayed_ref_root *delayed_refs;
+ struct btrfs_delayed_extent_op *extent_op;
+ struct btrfs_delayed_ref_node *ref;
+ int must_insert_reserved = 0;
+ int ret;
+
+ delayed_refs = &trans->transaction->delayed_refs;
+
+ while ((ref = select_delayed_ref(locked_ref))) {
+ if (ref->seq &&
+ btrfs_check_delayed_seq(fs_info, ref->seq)) {
+ spin_unlock(&locked_ref->lock);
+ unselect_delayed_ref_head(delayed_refs, locked_ref);
+ return -EAGAIN;
+ }
+
+ (*run_refs)++;
+ ref->in_tree = 0;
+ rb_erase_cached(&ref->ref_node, &locked_ref->ref_tree);
+ RB_CLEAR_NODE(&ref->ref_node);
+ if (!list_empty(&ref->add_list))
+ list_del(&ref->add_list);
+ /*
+ * When we play the delayed ref, also correct the ref_mod on
+ * head
+ */
+ switch (ref->action) {
+ case BTRFS_ADD_DELAYED_REF:
+ case BTRFS_ADD_DELAYED_EXTENT:
+ locked_ref->ref_mod -= ref->ref_mod;
+ break;
+ case BTRFS_DROP_DELAYED_REF:
+ locked_ref->ref_mod += ref->ref_mod;
+ break;
+ default:
+ WARN_ON(1);
+ }
+ atomic_dec(&delayed_refs->num_entries);
+
+ /*
+ * Record the must_insert_reserved flag before we drop the
+ * spin lock.
+ */
+ must_insert_reserved = locked_ref->must_insert_reserved;
+ locked_ref->must_insert_reserved = 0;
+
+ extent_op = locked_ref->extent_op;
+ locked_ref->extent_op = NULL;
+ spin_unlock(&locked_ref->lock);
+
+ ret = run_one_delayed_ref(trans, ref, extent_op,
+ must_insert_reserved);
+
+ btrfs_free_delayed_extent_op(extent_op);
+ if (ret) {
+ unselect_delayed_ref_head(delayed_refs, locked_ref);
+ btrfs_put_delayed_ref(ref);
+ btrfs_debug(fs_info, "run_one_delayed_ref returned %d",
+ ret);
+ return ret;
+ }
+
+ btrfs_put_delayed_ref(ref);
+ cond_resched();
+
+ spin_lock(&locked_ref->lock);
+ btrfs_merge_delayed_refs(trans, delayed_refs, locked_ref);
+ }
+
+ return 0;
+}
+
/*
* Returns 0 on success or if called with an already aborted transaction.
* Returns -ENOMEM or -EIO on failure and will abort the transaction.