From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 997DAC83F3A for ; Tue, 29 Aug 2023 08:41:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1693298480; h=from:from:sender:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:list-id:list-help: list-unsubscribe:list-subscribe:list-post; bh=kzCYK+m1dXoYq1GdX9wRq/xLcjMjzBwHZbogX1zaiXI=; b=B22KFacuCNPfZ02PFFgzQy+kF9LdLTxlcBnaa1pcoqaNtbTu49KxTtuewGxK8MIKbpk4mb vU17yPV0f3zNVByhWtIO1TuxukffZQIU7DMmHLENNoE6dR/EaWxQuoSfVD16HRk4kzfqms TokYttAiAirNT2B/Qznzyrrt3Ig0lCU= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-78-JkXm5MC5MkeHrykIZeV3gA-1; Tue, 29 Aug 2023 04:41:16 -0400 X-MC-Unique: JkXm5MC5MkeHrykIZeV3gA-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id EA25F8D40C1; Tue, 29 Aug 2023 08:41:15 +0000 (UTC) Received: from mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com [10.30.29.100]) by smtp.corp.redhat.com (Postfix) with ESMTP id E05A11121318; Tue, 29 Aug 2023 08:41:15 +0000 (UTC) Received: from mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (localhost [IPv6:::1]) by mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (Postfix) with ESMTP id A158819465BD; Tue, 29 Aug 2023 08:41:15 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) by mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (Postfix) with ESMTP id 83F681946588 for ; Tue, 29 Aug 2023 07:42:07 +0000 (UTC) Received: by smtp.corp.redhat.com (Postfix) id 694BC9A; Tue, 29 Aug 2023 07:42:07 +0000 (UTC) Received: from mimecast-mx02.redhat.com (mimecast04.extmail.prod.ext.rdu2.redhat.com [10.11.55.20]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 62A676B292 for ; Tue, 29 Aug 2023 07:42:07 +0000 (UTC) Received: from us-smtp-1.mimecast.com (us-smtp-1.mimecast.com [207.211.31.81]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 44E17101A53C for ; Tue, 29 Aug 2023 07:42:07 +0000 (UTC) Received: from out-242.mta1.migadu.com (out-242.mta1.migadu.com [95.215.58.242]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-199-1xFplw30MLyfzO6PDP0ryQ-1; Tue, 29 Aug 2023 03:42:04 -0400 X-MC-Unique: 1xFplw30MLyfzO6PDP0ryQ-1 Message-ID: Date: Tue, 29 Aug 2023 15:41:43 +0800 MIME-Version: 1.0 To: Matthew Wilcox References: <20230827132835.1373581-1-hao.xu@linux.dev> <20230827132835.1373581-3-hao.xu@linux.dev> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Hao Xu In-Reply-To: X-Migadu-Flow: FLOW_OUT X-Mimecast-Impersonation-Protect: Policy=CLT - Impersonation Protection Definition; Similar Internal Domain=false; Similar Monitored External Domain=false; Custom External Domain=false; Mimecast External Domain=false; Newly Observed Domain=false; Internal User Name=false; Custom Display Name List=false; Reply-to Address Mismatch=false; Targeted Threat Dictionary=false; Mimecast Threat Dictionary=false; Custom Threat Dictionary=false X-Scanned-By: MIMEDefang 3.1 on 10.11.54.5 X-Mailman-Approved-At: Tue, 29 Aug 2023 08:41:07 +0000 Subject: Re: [Cluster-devel] [PATCH 02/11] xfs: add NOWAIT semantics for readdir X-BeenThere: cluster-devel@redhat.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: "\[Cluster devel\]" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Wanpeng Li , "Darrick J . Wong" , Dominique Martinet , Dave Chinner , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Stefan Roesch , Clay Harris , linux-s390@vger.kernel.org, linux-nilfs@vger.kernel.org, codalist@coda.cs.cmu.edu, cluster-devel@redhat.com, linux-cachefs@redhat.com, linux-ext4@vger.kernel.org, devel@lists.orangefs.org, linux-cifs@vger.kernel.org, ecryptfs@vger.kernel.org, linux-nfs@vger.kernel.org, linux-block@vger.kernel.org, Alexander Viro , io-uring@vger.kernel.org, Jens Axboe , Christian Brauner , netdev@vger.kernel.org, samba-technical@lists.samba.org, linux-unionfs@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mtd@lists.infradead.org, bpf@vger.kernel.org, Pavel Begunkov , linux-btrfs@vger.kernel.org Errors-To: cluster-devel-bounces@redhat.com Sender: "Cluster-devel" X-Scanned-By: MIMEDefang 3.1 on 10.11.54.3 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: linux.dev Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 8/28/23 04:44, Matthew Wilcox wrote: > On Sun, Aug 27, 2023 at 09:28:26PM +0800, Hao Xu wrote: >> +++ b/fs/xfs/libxfs/xfs_da_btree.c >> @@ -2643,16 +2643,32 @@ xfs_da_read_buf( >> struct xfs_buf_map map, *mapp = ↦ >> int nmap = 1; >> int error; >> + int buf_flags = 0; >> >> *bpp = NULL; >> error = xfs_dabuf_map(dp, bno, flags, whichfork, &mapp, &nmap); >> if (error || !nmap) >> goto out_free; >> >> + /* >> + * NOWAIT semantics mean we don't wait on the buffer lock nor do we >> + * issue IO for this buffer if it is not already in memory. Caller will >> + * retry. This will return -EAGAIN if the buffer is in memory and cannot >> + * be locked, and no buffer and no error if it isn't in memory. We >> + * translate both of those into a return state of -EAGAIN and *bpp = >> + * NULL. >> + */ > > I would not include this comment. No strong comment here, since this patch is mostly from Dave, it's better if Dave can ack this. > >> + if (flags & XFS_DABUF_NOWAIT) >> + buf_flags |= XBF_TRYLOCK | XBF_INCORE; >> error = xfs_trans_read_buf_map(mp, tp, mp->m_ddev_targp, mapp, nmap, 0, >> &bp, ops); > > what tsting did you do with this? Because you don't actually _use_ > buf_flags anywhere in this patch (presumably they should be the > sixth argument to xfs_trans_read_buf_map() instead of 0). So I can only > conclude that either you didn't test, or your testing was inadequate. > The tests I've done are listed in the cover-letter, this one is missed, the tricky place is it's hard to get this kind of mistake since it runs well without nowait logic...I'll fix it in next version. >> if (error) >> goto out_free; >> + if (!bp) { >> + ASSERT(flags & XFS_DABUF_NOWAIT); > > I don't think this ASSERT is appropriate. > >> @@ -391,10 +401,17 @@ xfs_dir2_leaf_getdents( >> bp = NULL; >> } >> >> - if (*lock_mode == 0) >> - *lock_mode = xfs_ilock_data_map_shared(dp); >> + if (*lock_mode == 0) { >> + *lock_mode = >> + xfs_ilock_data_map_shared_generic(dp, >> + ctx->flags & DIR_CONTEXT_F_NOWAIT); >> + if (!*lock_mode) { >> + error = -EAGAIN; >> + break; >> + } >> + } > > 'generic' doesn't seem like a great suffix to mean 'takes nowait flag'. > And this is far too far indented. > > xfs_dir2_lock(dp, ctx, lock_mode); > > with: > > STATIC void xfs_dir2_lock(struct xfs_inode *dp, struct dir_context *ctx, > unsigned int lock_mode) > { > if (*lock_mode) > return; > if (ctx->flags & DIR_CONTEXT_F_NOWAIT) > return xfs_ilock_data_map_shared_nowait(dp); > return xfs_ilock_data_map_shared(dp); > } > > ... which I think you can use elsewhere in this patch (reformat it to > XFS coding style, of course). And then you don't need > xfs_ilock_data_map_shared_generic(). > How about rename xfs_ilock_data_map_shared() to xfs_ilock_data_map_block() and rename xfs_ilock_data_map_shared_generic() to xfs_ilock_data_map_shared()? STATIC void xfs_ilock_data_map_shared(struct xfs_inode *dp, struct dir_context *ctx, unsigned int lock_mode) { if (*lock_mode) return; if (ctx->flags & DIR_CONTEXT_F_NOWAIT) return xfs_ilock_data_map_shared_nowait(dp); return xfs_ilock_data_map_shared_block(dp); }