linux-kernel - Re: [f2fs-dev] [PATCH v3] f2fs: avoid inifinite loop to wait for flushing node pages at cp

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Message-ID: <92afae8b-2dd3-171a-562c-404a67f9aab2@huawei.com>
Date:   Tue, 26 May 2020 09:11:30 +0800
From:   Chao Yu <yuchao0@...wei.com>
To:     Jaegeuk Kim <jaegeuk@...nel.org>
CC:     <linux-kernel@...r.kernel.org>,
        <linux-f2fs-devel@...ts.sourceforge.net>, <kernel-team@...roid.com>
Subject: Re: [f2fs-dev] [PATCH v3] f2fs: avoid inifinite loop to wait for
 flushing node pages at cp_error

On 2020/5/25 23:06, Jaegeuk Kim wrote:
> On 05/25, Chao Yu wrote:
>> On 2020/5/25 11:56, Jaegeuk Kim wrote:
>>> Shutdown test is somtimes hung, since it keeps trying to flush dirty node pages
>>
>> IMO, for umount case, we should drop dirty reference and dirty pages on meta/data
>> pages like we change for node pages to avoid potential dead loop...
> 
> I believe we're doing for them. :P

Actually, I mean do we need to drop dirty meta/data pages explicitly as below:

diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 3dc3ac6fe143..4c08fd0a680a 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -299,8 +299,15 @@ static int __f2fs_write_meta_page(struct page *page,

 	trace_f2fs_writepage(page, META);

-	if (unlikely(f2fs_cp_error(sbi)))
+	if (unlikely(f2fs_cp_error(sbi))) {
+		if (is_sbi_flag_set(sbi, SBI_IS_CLOSE)) {
+			ClearPageUptodate(page);
+			dec_page_count(sbi, F2FS_DIRTY_META);
+			unlock_page(page);
+			return 0;
+		}
 		goto redirty_out;
+	}
 	if (unlikely(is_sbi_flag_set(sbi, SBI_POR_DOING)))
 		goto redirty_out;
 	if (wbc->for_reclaim && page->index < GET_SUM_BLOCK(sbi, 0))
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 48a622b95b76..94b342802513 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -2682,6 +2682,12 @@ int f2fs_write_single_data_page(struct page *page, int *submitted,

 	/* we should bypass data pages to proceed the kworkder jobs */
 	if (unlikely(f2fs_cp_error(sbi))) {
+		if (is_sbi_flag_set(sbi, SBI_IS_CLOSE)) {
+			ClearPageUptodate(page);
+			inode_dec_dirty_pages(inode);
+			unlock_page(page);
+			return 0;
+		}
 		mapping_set_error(page->mapping, -EIO);
 		/*
 		 * don't drop any dirty dentry pages for keeping lastest

> 
>>
>> Thanks,
>>
>>> in an inifinite loop. Let's drop dirty pages at umount in that case.
>>>
>>> Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
>>> ---
>>> v3:
>>>  - fix wrong unlock
>>>
>>> v2:
>>>  - fix typos
>>>
>>>  fs/f2fs/node.c | 9 ++++++++-
>>>  1 file changed, 8 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
>>> index e632de10aedab..e0bb0f7e0506e 100644
>>> --- a/fs/f2fs/node.c
>>> +++ b/fs/f2fs/node.c
>>> @@ -1520,8 +1520,15 @@ static int __write_node_page(struct page *page, bool atomic, bool *submitted,
>>>  
>>>  	trace_f2fs_writepage(page, NODE);
>>>  
>>> -	if (unlikely(f2fs_cp_error(sbi)))
>>> +	if (unlikely(f2fs_cp_error(sbi))) {
>>> +		if (is_sbi_flag_set(sbi, SBI_IS_CLOSE)) {
>>> +			ClearPageUptodate(page);
>>> +			dec_page_count(sbi, F2FS_DIRTY_NODES);
>>> +			unlock_page(page);
>>> +			return 0;
>>> +		}
>>>  		goto redirty_out;
>>> +	}
>>>  
>>>  	if (unlikely(is_sbi_flag_set(sbi, SBI_POR_DOING)))
>>>  		goto redirty_out;
>>>
> .
>