linux-kernel - Re: [f2fs-dev] [PATCH] Revert "f2fs: remove unreachable lazytime mount option parsing"

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Message-ID: <35c20e47-9124-45df-8067-67c5ef29600e@kernel.org>
Date: Wed, 20 Nov 2024 10:57:47 +0800
From: Chao Yu <chao@...nel.org>
To: Jaegeuk Kim <jaegeuk@...nel.org>
Cc: Chao Yu <chao@...nel.org>, Eric Sandeen <sandeen@...hat.com>,
 Daniel Rosenberg <drosen@...gle.com>, stable@...r.kernel.org,
 linux-kernel@...r.kernel.org, linux-f2fs-devel@...ts.sourceforge.net
Subject: Re: [f2fs-dev] [PATCH] Revert "f2fs: remove unreachable lazytime
 mount option parsing"

On 2024/11/20 4:48, Jaegeuk Kim wrote:
> On 11/19, Chao Yu wrote:
>> On 2024/11/13 5:39, Jaegeuk Kim via Linux-f2fs-devel wrote:
>>> Hi Eric,
>>>
>>> Could you please check this revert as it breaks the mount()?
>>> It seems F2FS needs to implement new mount support.
>>
>> Hi all,
>>
>> Actually, if we want to enable lazytime option, we can use mount
>> syscall as:
>>
>> mount("/dev/vdb", "/mnt/test", "f2fs", MS_LAZYTIME, NULL);
>>
>> or use shell script as:
>>
>> mount -t f2fs -o lazytime /dev/vdb /mnt/test
>>
>> IIUC, the reason why mount command can handle lazytime is, after
>> 8c7f073aaeaa ("libmount: add support for MS_LAZYTIME"), mount command
>> supports to map "lazytime" to MS_LAZYTIME, and use MS_LAZYTIME in
>> parameter @mountflags of mount(2).
>>
>> So, it looks we have alternative way to enable/disable lazytime feature
>> after removing Opt_{no,}lazytime parsing in f2fs, do we really need this
>> revert patch?
> 
> This is a regression of the below command. I don't think offering others are
> feasible.
> 
> mount("/dev/vdb", "/mnt/test", "f2fs", 0, "lazytime");

Alright, there are other options were removed along w/ removal of
related feature. e.g.

1. io_bits=%u by commit 87161a2b0aed ("f2fs: deprecate io_bits")
2. whint_mode=%s by commit 930e2607638d ("f2fs: remove obsolete whint_mode")

Do we need to add these options handling back, and print "xxx options were
deprecated" as we did in ("f2fs: kill heap-based allocation"), in order to
avoid mount(......, "io_bits=%u" or "whint_mode=%s") command regression?

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 867b147eb957..329f317e6f09 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -733,10 +733,8 @@ static int parse_options(struct super_block *sb, char *options, bool is_remount)
  			clear_opt(sbi, DISCARD);
  			break;
  		case Opt_noheap:
-			set_opt(sbi, NOHEAP);
-			break;
  		case Opt_heap:
-			clear_opt(sbi, NOHEAP);
+			f2fs_warn(sbi, "heap/no_heap options were deprecated");
  			break;

Thanks,

> 
>>
>> Thanks,
>>
>>>
>>> Thanks,
>>>
>>> On 11/12, Jaegeuk Kim wrote:
>>>> This reverts commit 54f43a10fa257ad4af02a1d157fefef6ebcfa7dc.
>>>>
>>>> The above commit broke the lazytime mount, given
>>>>
>>>> mount("/dev/vdb", "/mnt/test", "f2fs", 0, "lazytime");
>>>>
>>>> CC: stable@...r.kernel.org # 6.11+
>>>> Signed-off-by: Daniel Rosenberg <drosen@...gle.com>
>>>> Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
>>>> ---
>>>>    fs/f2fs/super.c | 10 ++++++++++
>>>>    1 file changed, 10 insertions(+)
>>>>
>>>> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
>>>> index 49519439b770..35c4394e4fc6 100644
>>>> --- a/fs/f2fs/super.c
>>>> +++ b/fs/f2fs/super.c
>>>> @@ -150,6 +150,8 @@ enum {
>>>>    	Opt_mode,
>>>>    	Opt_fault_injection,
>>>>    	Opt_fault_type,
>>>> +	Opt_lazytime,
>>>> +	Opt_nolazytime,
>>>>    	Opt_quota,
>>>>    	Opt_noquota,
>>>>    	Opt_usrquota,
>>>> @@ -226,6 +228,8 @@ static match_table_t f2fs_tokens = {
>>>>    	{Opt_mode, "mode=%s"},
>>>>    	{Opt_fault_injection, "fault_injection=%u"},
>>>>    	{Opt_fault_type, "fault_type=%u"},
>>>> +	{Opt_lazytime, "lazytime"},
>>>> +	{Opt_nolazytime, "nolazytime"},
>>>>    	{Opt_quota, "quota"},
>>>>    	{Opt_noquota, "noquota"},
>>>>    	{Opt_usrquota, "usrquota"},
>>>> @@ -922,6 +926,12 @@ static int parse_options(struct super_block *sb, char *options, bool is_remount)
>>>>    			f2fs_info(sbi, "fault_type options not supported");
>>>>    			break;
>>>>    #endif
>>>> +		case Opt_lazytime:
>>>> +			sb->s_flags |= SB_LAZYTIME;
>>>> +			break;
>>>> +		case Opt_nolazytime:
>>>> +			sb->s_flags &= ~SB_LAZYTIME;
>>>> +			break;
>>>>    #ifdef CONFIG_QUOTA
>>>>    		case Opt_quota:
>>>>    		case Opt_usrquota:
>>>> -- 
>>>> 2.47.0.277.g8800431eea-goog
>>>
>>>
>>> _______________________________________________
>>> Linux-f2fs-devel mailing list
>>> Linux-f2fs-devel@...ts.sourceforge.net
>>> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel