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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 49361C83F15 for ; Sun, 27 Aug 2023 20:45:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229631AbjH0UpZ (ORCPT ); Sun, 27 Aug 2023 16:45:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45842 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229546AbjH0UpR (ORCPT ); Sun, 27 Aug 2023 16:45:17 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 892F8BF; Sun, 27 Aug 2023 13:45:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=b31OO6Xd9+jxzKw5QB3n4d33iA6sZ4nPi+nMylKSno4=; b=rh2eHyjfSChvP5M3GZFqng0djt iCSjqmEmDczFMnSTrKUt8mmVXGPGgbJ4oq2lIEXyRSbFH+YR4YMUxP/z9QQKohjOoCQZks3WE0IMK 3S4hJ/QxWWGwrLIXBI8vnsgZg3HMNGIE+hIRemTa2iQvkDDHCCMd0yz1djBYQiyi1qOQAKg4GjHdy fEL5cINLesPqAO5iR1xTPAPnXU+iFHAHJEGUTx86DeTnZzv1uxgeaR21j4BV+7nscvIXdd9sVE/Si rCIGIbVvaskI417AUCK4HwQeBGpvqIcrg+ypempVGeBQFeEiZBUSg5QboubLY+HaM/1Y954EFPxgD hXmevJ/g==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1qaMcv-00Dkeb-PH; Sun, 27 Aug 2023 20:44:53 +0000 Date: Sun, 27 Aug 2023 21:44:53 +0100 From: Matthew Wilcox To: Hao Xu Cc: io-uring@vger.kernel.org, Jens Axboe , Dominique Martinet , Pavel Begunkov , Christian Brauner , Alexander Viro , Stefan Roesch , Clay Harris , Dave Chinner , "Darrick J . Wong" , linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org, linux-ext4@vger.kernel.org, linux-cachefs@redhat.com, ecryptfs@vger.kernel.org, linux-nfs@vger.kernel.org, linux-unionfs@vger.kernel.org, bpf@vger.kernel.org, netdev@vger.kernel.org, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, linux-btrfs@vger.kernel.org, codalist@coda.cs.cmu.edu, linux-f2fs-devel@lists.sourceforge.net, cluster-devel@redhat.com, linux-mm@kvack.org, linux-nilfs@vger.kernel.org, devel@lists.orangefs.org, linux-cifs@vger.kernel.org, samba-technical@lists.samba.org, linux-mtd@lists.infradead.org, Wanpeng Li Subject: Re: [PATCH 02/11] xfs: add NOWAIT semantics for readdir Message-ID: References: <20230827132835.1373581-1-hao.xu@linux.dev> <20230827132835.1373581-3-hao.xu@linux.dev> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230827132835.1373581-3-hao.xu@linux.dev> Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org 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. > + 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. > 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().