@@ -1928,12 +1928,13 @@ int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
if (file->private_data)
btrfs_ioctl_trans_end(file);
- trans = btrfs_start_transaction(root, 0);
+ trans = btrfs_join_transaction(root);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
mutex_unlock(&inode->i_mutex);
goto out;
}
+ trans->sync = true;
ret = btrfs_log_dentry_safe(trans, root, dentry);
if (ret < 0) {
@@ -474,6 +474,7 @@ again:
h->type = type;
h->allocating_chunk = false;
h->reloc_reserved = false;
+ h->sync = false;
INIT_LIST_HEAD(&h->qgroup_ref_list);
INIT_LIST_HEAD(&h->new_bgs);
@@ -713,7 +714,7 @@ static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
btrfs_create_pending_block_groups(trans, root);
trans->delayed_ref_updates = 0;
- if (btrfs_should_throttle_delayed_refs(trans, root)) {
+ if (!trans->sync && btrfs_should_throttle_delayed_refs(trans, root)) {
cur = max_t(unsigned long, cur, 1);
trans->delayed_ref_updates = 0;
btrfs_run_delayed_refs(trans, root, cur);
@@ -93,6 +93,7 @@ struct btrfs_trans_handle {
short adding_csums;
bool allocating_chunk;
bool reloc_reserved;
+ bool sync;
unsigned int type;
/*
* this root is only needed to validate that the root passed to
Looking into some performance related issues with large amounts of metadata revealed that we can have some pretty huge swings in fsync() performance. If we have a lot of delayed refs backed up (as you will tend to do with lots of metadata) fsync() will wander off and try to run some of those delayed refs which can result in reading from disk and such. Since the actual act of fsync() doesn't create any delayed refs there is no need to make it throttle on delayed ref stuff, that will be handled by other people. We also use btrfs_start_transaction() which is also less than optimal if we're at the beginning stage of committing the transaction somewhere. With this patch we get much smoother fsync performance with large amounts of metadata. Thanks, Signed-off-by: Josef Bacik <jbacik@fb.com> --- fs/btrfs/file.c | 3 ++- fs/btrfs/transaction.c | 3 ++- fs/btrfs/transaction.h | 1 + 3 files changed, 5 insertions(+), 2 deletions(-)