From: Jaegeuk Kim <jaegeuk@kernel.org>
To: Sayali Lokhande <sayalil@codeaurora.org>
Cc: linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net
Subject: Re: [f2fs-dev] [PATCH] f2fs: Avoid double lock for cp_rwsem
Date: Thu, 23 Apr 2020 17:16:19 -0700 [thread overview]
Message-ID: <20200424001619.GA109617@google.com> (raw)
In-Reply-To: <20200423201922.GB99191@google.com>
On 04/23, Jaegeuk Kim wrote:
> On 04/23, Sayali Lokhande wrote:
> > Call stack :
> > f2fs_write_checkpoint()
> > -> block_operations(sbi)
> > f2fs_lock_all(sbi);
> > down_write(&sbi->cp_rwsem); => write lock held
> > <>
> > -> f2fs_sync_node_pages()
> > if (is_inline_node(page))
> > flush_inline_data()
> > page = f2fs_pagecache_get_page()
> > if (!page)
> > goto iput_out;
> > iput_out:
> > iput(inode);
> > -> f2fs_evict_inode()
> > f2fs_truncate_blocks()
> > f2fs_lock_op()
> > down_read(&sbi->cp_rwsem); => read lock fail
>
> How about this, since we don't actually need to flush inline_data?
Hmm, nvm. This causes no space panic regressed during xfstests.
>
> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
> index 4da0d8713df5c..9af8d5319fdd3 100644
> --- a/fs/f2fs/node.c
> +++ b/fs/f2fs/node.c
> @@ -1871,7 +1871,7 @@ int f2fs_sync_node_pages(struct f2fs_sb_info *sbi,
> }
>
> /* flush inline_data */
> - if (is_inline_node(page)) {
> + if (is_inline_node(page) && io_type != FS_CP_NODE_IO) {
> clear_inline_node(page);
> unlock_page(page);
> flush_inline_data(sbi, ino_of_node(page));
>
> >
> > Signed-off-by: Sayali Lokhande <sayalil@codeaurora.org>
> > ---
> > fs/f2fs/checkpoint.c | 10 ++++------
> > 1 file changed, 4 insertions(+), 6 deletions(-)
> >
> > diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
> > index 5ba649e..5c504cf 100644
> > --- a/fs/f2fs/checkpoint.c
> > +++ b/fs/f2fs/checkpoint.c
> > @@ -1219,21 +1219,19 @@ static int block_operations(struct f2fs_sb_info *sbi)
> > goto retry_flush_quotas;
> > }
> >
> > -retry_flush_nodes:
> > down_write(&sbi->node_write);
> >
> > if (get_pages(sbi, F2FS_DIRTY_NODES)) {
> > up_write(&sbi->node_write);
> > + f2fs_unlock_all(sbi);
> > atomic_inc(&sbi->wb_sync_req[NODE]);
> > err = f2fs_sync_node_pages(sbi, &wbc, false, FS_CP_NODE_IO);
> > atomic_dec(&sbi->wb_sync_req[NODE]);
> > - if (err) {
> > - up_write(&sbi->node_change);
> > - f2fs_unlock_all(sbi);
> > + up_write(&sbi->node_change);
> > + if (err)
> > goto out;
> > - }
> > cond_resched();
> > - goto retry_flush_nodes;
> > + goto retry_flush_quotas;
> > }
> >
> > /*
> > --
> > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> > a Linux Foundation Collaborative Project
>
>
> _______________________________________________
> Linux-f2fs-devel mailing list
> Linux-f2fs-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
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next prev parent reply other threads:[~2020-04-24 0:16 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-23 10:13 [f2fs-dev] [PATCH] f2fs: Avoid double lock for cp_rwsem Sayali Lokhande
2020-04-23 13:13 ` Chao Yu
2020-04-23 20:19 ` Jaegeuk Kim
2020-04-24 0:16 ` Jaegeuk Kim [this message]
2020-04-23 13:07 Markus Elfring
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