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 554ECC433F5 for ; Thu, 29 Sep 2022 11:36:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235310AbiI2Lge (ORCPT ); Thu, 29 Sep 2022 07:36:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57244 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232380AbiI2Lgd (ORCPT ); Thu, 29 Sep 2022 07:36:33 -0400 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8BCB813C846; Thu, 29 Sep 2022 04:36:32 -0700 (PDT) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 3B7F71F388; Thu, 29 Sep 2022 11:36:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1664451391; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=xMRJe1MU1ptYwTyQ+JepMZmanBEMC61aFRA+CflrhZU=; b=rAISbCTn0I1rjrXjAraHtB+HRHHuhe3fp6fgjCjCHK6qP2I5fuppESrN5U2bKXOkQmxeed BxqKDYqtb9Vc+EsvriwWuMaU4oZmHKOiq53AToxmve4hrlC5MWvIf0ZVj3K1B6qQ3SYRvq 325DWAoKxdSK8ksM0ZFR4FIz9Aou/os= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1664451391; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=xMRJe1MU1ptYwTyQ+JepMZmanBEMC61aFRA+CflrhZU=; b=x+MK6pVvnlyjLFCpv7YrIQQUYebfY/BJoIXqBNqZVzM1O3JHSyHJhivYZ6aQ0YwjO5Miqq 74JOf0iLBNteSODQ== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 2D2041348E; Thu, 29 Sep 2022 11:36:31 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id E576Cj+DNWNocgAAMHmgww (envelope-from ); Thu, 29 Sep 2022 11:36:31 +0000 Received: by quack3.suse.cz (Postfix, from userid 1000) id 7DEECA0681; Thu, 29 Sep 2022 13:36:30 +0200 (CEST) Date: Thu, 29 Sep 2022 13:36:30 +0200 From: Jan Kara To: Ojaswin Mujoo Cc: linux-ext4@vger.kernel.org, Theodore Ts'o , Ritesh Harjani , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Andreas Dilger , Jan Kara , rookxu , Ritesh Harjani Subject: Re: [RFC v3 5/8] ext4: Abstract out overlap fix/check logic in ext4_mb_normalize_request() Message-ID: <20220929113630.xdergbnbru63q6s7@quack3> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On Tue 27-09-22 14:46:45, Ojaswin Mujoo wrote: > Abstract out the logic of fixing PA overlaps in ext4_mb_normalize_request to > improve readability of code. This also makes it easier to make changes > to the overlap logic in future. > > There are no functional changes in this patch > > Signed-off-by: Ojaswin Mujoo > Reviewed-by: Ritesh Harjani (IBM) Looks good. Feel free to add: Reviewed-by: Jan Kara Honza > --- > fs/ext4/mballoc.c | 110 +++++++++++++++++++++++++++++----------------- > 1 file changed, 69 insertions(+), 41 deletions(-) > > diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c > index d1ce34888dcc..dda9a72c81d9 100644 > --- a/fs/ext4/mballoc.c > +++ b/fs/ext4/mballoc.c > @@ -4008,6 +4008,74 @@ ext4_mb_pa_assert_overlap(struct ext4_allocation_context *ac, > rcu_read_unlock(); > } > > +/* > + * Given an allocation context "ac" and a range "start", "end", check > + * and adjust boundaries if the range overlaps with any of the existing > + * preallocatoins stored in the corresponding inode of the allocation context. > + * > + *Parameters: > + * ac allocation context > + * start start of the new range > + * end end of the new range > + */ > +static inline void > +ext4_mb_pa_adjust_overlap(struct ext4_allocation_context *ac, > + ext4_lblk_t *start, ext4_lblk_t *end) > +{ > + struct ext4_inode_info *ei = EXT4_I(ac->ac_inode); > + struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); > + struct ext4_prealloc_space *tmp_pa; > + ext4_lblk_t new_start, new_end; > + ext4_lblk_t tmp_pa_start, tmp_pa_end; > + > + new_start = *start; > + new_end = *end; > + > + /* check we don't cross already preallocated blocks */ > + rcu_read_lock(); > + list_for_each_entry_rcu(tmp_pa, &ei->i_prealloc_list, pa_inode_list) { > + if (tmp_pa->pa_deleted) > + continue; > + spin_lock(&tmp_pa->pa_lock); > + if (tmp_pa->pa_deleted) { > + spin_unlock(&tmp_pa->pa_lock); > + continue; > + } > + > + tmp_pa_start = tmp_pa->pa_lstart; > + tmp_pa_end = tmp_pa->pa_lstart + EXT4_C2B(sbi, tmp_pa->pa_len); > + > + /* PA must not overlap original request */ > + BUG_ON(!(ac->ac_o_ex.fe_logical >= tmp_pa_end || > + ac->ac_o_ex.fe_logical < tmp_pa_start)); > + > + /* skip PAs this normalized request doesn't overlap with */ > + if (tmp_pa_start >= new_end || tmp_pa_end <= new_start) { > + spin_unlock(&tmp_pa->pa_lock); > + continue; > + } > + BUG_ON(tmp_pa_start <= new_start && tmp_pa_end >= new_end); > + > + /* adjust start or end to be adjacent to this pa */ > + if (tmp_pa_end <= ac->ac_o_ex.fe_logical) { > + BUG_ON(tmp_pa_end < new_start); > + new_start = tmp_pa_end; > + } else if (tmp_pa_start > ac->ac_o_ex.fe_logical) { > + BUG_ON(tmp_pa_start > new_end); > + new_end = tmp_pa_start; > + } > + spin_unlock(&tmp_pa->pa_lock); > + } > + rcu_read_unlock(); > + > + /* XXX: extra loop to check we really don't overlap preallocations */ > + ext4_mb_pa_assert_overlap(ac, new_start, new_end); > + > + *start = new_start; > + *end = new_end; > + return; > +} > + > /* > * Normalization means making request better in terms of > * size and alignment > @@ -4022,9 +4090,6 @@ ext4_mb_normalize_request(struct ext4_allocation_context *ac, > loff_t size, start_off; > loff_t orig_size __maybe_unused; > ext4_lblk_t start; > - struct ext4_inode_info *ei = EXT4_I(ac->ac_inode); > - struct ext4_prealloc_space *tmp_pa; > - ext4_lblk_t tmp_pa_start, tmp_pa_end; > > /* do normalize only data requests, metadata requests > do not need preallocation */ > @@ -4125,47 +4190,10 @@ ext4_mb_normalize_request(struct ext4_allocation_context *ac, > > end = start + size; > > - /* check we don't cross already preallocated blocks */ > - rcu_read_lock(); > - list_for_each_entry_rcu(tmp_pa, &ei->i_prealloc_list, pa_inode_list) { > - if (tmp_pa->pa_deleted) > - continue; > - spin_lock(&tmp_pa->pa_lock); > - if (tmp_pa->pa_deleted) { > - spin_unlock(&tmp_pa->pa_lock); > - continue; > - } > - > - tmp_pa_start = tmp_pa->pa_lstart; > - tmp_pa_end = tmp_pa->pa_lstart + EXT4_C2B(sbi, tmp_pa->pa_len); > - > - /* PA must not overlap original request */ > - BUG_ON(!(ac->ac_o_ex.fe_logical >= tmp_pa_end || > - ac->ac_o_ex.fe_logical < tmp_pa_start)); > - > - /* skip PAs this normalized request doesn't overlap with */ > - if (tmp_pa_start >= end || tmp_pa_end <= start) { > - spin_unlock(&tmp_pa->pa_lock); > - continue; > - } > - BUG_ON(tmp_pa_start <= start && tmp_pa_end >= end); > + ext4_mb_pa_adjust_overlap(ac, &start, &end); > > - /* adjust start or end to be adjacent to this pa */ > - if (tmp_pa_end <= ac->ac_o_ex.fe_logical) { > - BUG_ON(tmp_pa_end < start); > - start = tmp_pa_end; > - } else if (tmp_pa_start > ac->ac_o_ex.fe_logical) { > - BUG_ON(tmp_pa_start > end); > - end = tmp_pa_start; > - } > - spin_unlock(&tmp_pa->pa_lock); > - } > - rcu_read_unlock(); > size = end - start; > > - /* XXX: extra loop to check we really don't overlap preallocations */ > - ext4_mb_pa_assert_overlap(ac, start, end); > - > /* > * In this function "start" and "size" are normalized for better > * alignment and length such that we could preallocate more blocks. > -- > 2.31.1 > -- Jan Kara SUSE Labs, CR