Message ID | 20230406150621.3854298-1-chao@kernel.org |
---|---|
State | New |
Headers |
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[2620:137:e000::1:20]) by mx.google.com with ESMTP id dd18-20020a1709069b9200b009281f44dc1fsi1791046ejc.270.2023.04.06.08.13.23; Thu, 06 Apr 2023 08:13:48 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=k20201202 header.b=TZNcy5xB; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239552AbjDFPGd (ORCPT <rfc822;lkml4gm@gmail.com> + 99 others); Thu, 6 Apr 2023 11:06:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56686 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239455AbjDFPGb (ORCPT <rfc822;linux-kernel@vger.kernel.org>); Thu, 6 Apr 2023 11:06:31 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BA1E31AB; Thu, 6 Apr 2023 08:06:30 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 4BF2C618D3; Thu, 6 Apr 2023 15:06:30 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5A743C433D2; Thu, 6 Apr 2023 15:06:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1680793589; bh=/Qnxu3y/b9dYJicRMfW3kfoy3najo7T//JwcFvG+lLE=; h=From:To:Cc:Subject:Date:From; b=TZNcy5xBFCrr2jp9YctQlD+Z2BrBKdv6vudCxvkz8cJuGXr+3031ZlwTHdz2lS9Wo GegbTIGxoJi2BBvRgbmYlw1XUaWsQ1k8hc47ySkxYQWe0X3v2Lt2U+8vof5LrnKTio Nk356Yic+9tkc68SYCfKG77yHhfa9T+4Bx0aTH07lhO66blM4LLCZ1ExuqPT/n1qDf 8FaBV6MkK96K0/HoKnPGcq9HTdRt0PUdPK4hJqLv07SSdUI2xfpEIbyU+LNrWdieEm Q4yz+KqlhHfsOGz5gF/XtBJfFzADqr2D0FdRtZe9HaYFa+oRXW+58dVozhu77XGvLO vn6gSnGqYFi4w== From: Chao Yu <chao@kernel.org> To: Theodore Ts'o <tytso@mit.edu>, Andreas Dilger <adilger.kernel@dilger.ca> Cc: linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, Chao Yu <chao@kernel.org> Subject: [PATCH] ext4: fix wrong calculation of minlen in ext4_trim_fs() Date: Thu, 6 Apr 2023 23:06:21 +0800 Message-Id: <20230406150621.3854298-1-chao@kernel.org> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-2.5 required=5.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_MED,SPF_HELO_NONE, SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: <linux-kernel.vger.kernel.org> X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1762440279137615899?= X-GMAIL-MSGID: =?utf-8?q?1762440279137615899?= |
Series |
ext4: fix wrong calculation of minlen in ext4_trim_fs()
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Commit Message
Chao Yu
April 6, 2023, 3:06 p.m. UTC
As Ted pointed out as below:
"
However the minlen variable in ext4_trim_fs is in units of *clusters*.
And so it gets rounded up two places. The first time is when it is
converted into units of a cluster:
minlen = EXT4_NUM_B2C(EXT4_SB(sb),
range->minlen >> sb->s_blocksize_bits);
Oh, and by the way, that first conversion is not correct as currently
written in ext4_fs_trim(). It should be
minlen = (range->minlen + EXT4_CLUSTER_SIZE(sb) - 1) >>
(sb->s_blocksize_bits + EXT4_CLUSTER_BITS(sb));
"
The reason is if range->minlen is smaller than block size of ext4,
original calculation "range->minlen >> sb->s_blocksize_bits" may
return zero, but since EXT4_NUM_B2C() expects a non-zero in-parameter,
so it needs to round up range->minlen to cluster size directly as above.
Link: https://lore.kernel.org/lkml/20230311031843.GF860405@mit.edu/
Suggested-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Chao Yu <chao@kernel.org>
---
fs/ext4/mballoc.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
Comments
On Thu 06-04-23 23:06:21, Chao Yu wrote: > As Ted pointed out as below: > > " > However the minlen variable in ext4_trim_fs is in units of *clusters*. > And so it gets rounded up two places. The first time is when it is > converted into units of a cluster: > > minlen = EXT4_NUM_B2C(EXT4_SB(sb), > range->minlen >> sb->s_blocksize_bits); > > Oh, and by the way, that first conversion is not correct as currently > written in ext4_fs_trim(). It should be > > minlen = (range->minlen + EXT4_CLUSTER_SIZE(sb) - 1) >> > (sb->s_blocksize_bits + EXT4_CLUSTER_BITS(sb)); > " > > The reason is if range->minlen is smaller than block size of ext4, > original calculation "range->minlen >> sb->s_blocksize_bits" may > return zero, but since EXT4_NUM_B2C() expects a non-zero in-parameter, > so it needs to round up range->minlen to cluster size directly as above. > > Link: https://lore.kernel.org/lkml/20230311031843.GF860405@mit.edu/ > Suggested-by: Theodore Ts'o <tytso@mit.edu> > Signed-off-by: Chao Yu <chao@kernel.org> Looks good to me. Feel free to add: Reviewed-by: Jan Kara <jack@suse.cz> Honza > --- > fs/ext4/mballoc.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c > index 5b2ae37a8b80..d8b9d6a83d1e 100644 > --- a/fs/ext4/mballoc.c > +++ b/fs/ext4/mballoc.c > @@ -6478,8 +6478,8 @@ int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range) > > start = range->start >> sb->s_blocksize_bits; > end = start + (range->len >> sb->s_blocksize_bits) - 1; > - minlen = EXT4_NUM_B2C(EXT4_SB(sb), > - range->minlen >> sb->s_blocksize_bits); > + minlen = (range->minlen + EXT4_CLUSTER_SIZE(sb) - 1) >> > + (sb->s_blocksize_bits + EXT4_CLUSTER_BITS(sb)); > > if (minlen > EXT4_CLUSTERS_PER_GROUP(sb) || > start >= max_blks || > -- > 2.25.1 >
Ping, On 2023/4/21 17:35, Jan Kara wrote: > On Thu 06-04-23 23:06:21, Chao Yu wrote: >> As Ted pointed out as below: >> >> " >> However the minlen variable in ext4_trim_fs is in units of *clusters*. >> And so it gets rounded up two places. The first time is when it is >> converted into units of a cluster: >> >> minlen = EXT4_NUM_B2C(EXT4_SB(sb), >> range->minlen >> sb->s_blocksize_bits); >> >> Oh, and by the way, that first conversion is not correct as currently >> written in ext4_fs_trim(). It should be >> >> minlen = (range->minlen + EXT4_CLUSTER_SIZE(sb) - 1) >> >> (sb->s_blocksize_bits + EXT4_CLUSTER_BITS(sb)); >> " >> >> The reason is if range->minlen is smaller than block size of ext4, >> original calculation "range->minlen >> sb->s_blocksize_bits" may >> return zero, but since EXT4_NUM_B2C() expects a non-zero in-parameter, >> so it needs to round up range->minlen to cluster size directly as above. >> >> Link: https://lore.kernel.org/lkml/20230311031843.GF860405@mit.edu/ >> Suggested-by: Theodore Ts'o <tytso@mit.edu> >> Signed-off-by: Chao Yu <chao@kernel.org> > > Looks good to me. Feel free to add: > > Reviewed-by: Jan Kara <jack@suse.cz> > > Honza > >> --- >> fs/ext4/mballoc.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c >> index 5b2ae37a8b80..d8b9d6a83d1e 100644 >> --- a/fs/ext4/mballoc.c >> +++ b/fs/ext4/mballoc.c >> @@ -6478,8 +6478,8 @@ int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range) >> >> start = range->start >> sb->s_blocksize_bits; >> end = start + (range->len >> sb->s_blocksize_bits) - 1; >> - minlen = EXT4_NUM_B2C(EXT4_SB(sb), >> - range->minlen >> sb->s_blocksize_bits); >> + minlen = (range->minlen + EXT4_CLUSTER_SIZE(sb) - 1) >> >> + (sb->s_blocksize_bits + EXT4_CLUSTER_BITS(sb)); >> >> if (minlen > EXT4_CLUSTERS_PER_GROUP(sb) || >> start >= max_blks || >> -- >> 2.25.1 >>
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 5b2ae37a8b80..d8b9d6a83d1e 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -6478,8 +6478,8 @@ int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range) start = range->start >> sb->s_blocksize_bits; end = start + (range->len >> sb->s_blocksize_bits) - 1; - minlen = EXT4_NUM_B2C(EXT4_SB(sb), - range->minlen >> sb->s_blocksize_bits); + minlen = (range->minlen + EXT4_CLUSTER_SIZE(sb) - 1) >> + (sb->s_blocksize_bits + EXT4_CLUSTER_BITS(sb)); if (minlen > EXT4_CLUSTERS_PER_GROUP(sb) || start >= max_blks ||