From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from firstgate.proxmox.com (firstgate.proxmox.com [212.224.123.68]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.proxmox.com (Postfix) with ESMTPS id 8BEEE6C5CC for ; Mon, 29 Mar 2021 15:22:04 +0200 (CEST) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id 7E0C815C22 for ; Mon, 29 Mar 2021 15:22:04 +0200 (CEST) Received: from proxmox-new.maurer-it.com (proxmox-new.maurer-it.com [212.186.127.180]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by firstgate.proxmox.com (Proxmox) with ESMTPS id F3BDC15C17 for ; Mon, 29 Mar 2021 15:22:03 +0200 (CEST) Received: from proxmox-new.maurer-it.com (localhost.localdomain [127.0.0.1]) by proxmox-new.maurer-it.com (Proxmox) with ESMTP id C3B5042D52 for ; Mon, 29 Mar 2021 15:22:03 +0200 (CEST) Date: Mon, 29 Mar 2021 15:22:02 +0200 From: Wolfgang Bumiller To: Dominik Csapak Cc: pbs-devel@lists.proxmox.com Message-ID: <20210329132202.gpcarjyodroy5bim@wobu-vie.proxmox.com> References: <20210324105638.32493-1-d.csapak@proxmox.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210324105638.32493-1-d.csapak@proxmox.com> User-Agent: NeoMutt/20180716 X-SPAM-LEVEL: Spam detection results: 0 AWL 0.028 Adjusted score from AWL reputation of From: address KAM_DMARC_STATUS 0.01 Test Rule for DKIM or SPF Failure with Strict Alignment RCVD_IN_DNSWL_MED -2.3 Sender listed at https://www.dnswl.org/, medium trust SPF_HELO_NONE 0.001 SPF: HELO does not publish an SPF Record SPF_PASS -0.001 SPF: sender matches SPF record Subject: Re: [pbs-devel] [PATCH pxar] encoder: flush after writing last entry X-BeenThere: pbs-devel@lists.proxmox.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: Proxmox Backup Server development discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 29 Mar 2021 13:22:04 -0000 On Wed, Mar 24, 2021 at 11:56:38AM +0100, Dominik Csapak wrote: > some writers may need to be flushed to write out all data > > Signed-off-by: Dominik Csapak > --- > for now, it is not needed because in all code paths we use it > the writers do not need to be flushed, but there is no guarantee > it will stay that way > > src/encoder/mod.rs | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/src/encoder/mod.rs b/src/encoder/mod.rs > index 1004efa..c114657 100644 > --- a/src/encoder/mod.rs > +++ b/src/encoder/mod.rs > @@ -83,6 +83,13 @@ async fn seq_write( > Ok(put) > } > > +/// awaitable version of 'poll_flush'. > +async fn flush( > + output: &mut T, > +) -> io::Result<()> { > + poll_fn(|cx| unsafe { Pin::new_unchecked(&mut *output).poll_flush(cx) }).await > +} > + > /// Write the entire contents of a buffer, handling short writes. > async fn seq_write_all( > output: &mut T, > @@ -715,6 +722,8 @@ impl<'a, T: SeqWrite + 'a> EncoderImpl<'a, T> { > ) > .await?; > > + flush(self.output.as_mut()).await?; According to the patch comment this hasn't broken anywhere at the time, but was there any test-code that did need this? I'd like to make this at least conditional on the writer being `EncoderOutput::Owned` to not cause additional flushes for every single level of directory nesting. That said, I'm not even convinced an `Owned` writer would really need this? You don't need to explicitly call `flush()` on a `std::fs::File` or even a `std::io::BufWriter` explicitly (`BufWriter` explicitly flushes in its `Drop` handler), unless you *explicitly* want to handle its error, but then you should keep ownership of the writer you pass to the encoder anyway and flush manually, not leave that up to the pxar code.