Hi Jaegeuk,
On 2017/7/22 4:54, Jaegeuk Kim wrote:
> Hi Chao,
>
> On 07/21, Chao Yu wrote:
>> When ->freeze_fs is called from lvm for doing snapshot, it needs to
>> make sure there will be no more changes in filesystem's data, however,
>> previously, background GC wasn't aware of freezing, so in environment
>> with active background GC thread, data of snapshot becomes unstable.
>
> What about flush/discard threads?
Updated.
Thanks,
>
> Thanks,
>
>>
>> This patch fixes this issue by adding sb_{start,end}_intwrite in GC
>> flow.
>>
>> Signed-off-by: Chao Yu <yuch...@huawei.com>
>> ---
>> fs/f2fs/gc.c | 8 ++++++--
>> 1 file changed, 6 insertions(+), 2 deletions(-)
>>
>> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
>> index 76ad2c3d88db..1c0117f60083 100644
>> --- a/fs/f2fs/gc.c
>> +++ b/fs/f2fs/gc.c
>> @@ -55,6 +55,8 @@ static int gc_thread_func(void *data)
>> }
>> #endif
>>
>> + sb_start_intwrite(sbi->sb);
>> +
>> /*
>> * [GC triggering condition]
>> * 0. GC is not conducted currently.
>> @@ -69,12 +71,12 @@ static int gc_thread_func(void *data)
>> * So, I'd like to wait some time to collect dirty segments.
>> */
>> if (!mutex_trylock(&sbi->gc_mutex))
>> - continue;
>> + goto next;
>>
>> if (!is_idle(sbi)) {
>> increase_sleep_time(gc_th, &wait_ms);
>> mutex_unlock(&sbi->gc_mutex);
>> - continue;
>> + goto next;
>> }
>>
>> if (has_enough_invalid_blocks(sbi))
>> @@ -93,6 +95,8 @@ static int gc_thread_func(void *data)
>>
>> /* balancing f2fs's metadata periodically */
>> f2fs_balance_fs_bg(sbi);
>> +next:
>> + sb_end_intwrite(sbi->sb);
>>
>> } while (!kthread_should_stop());
>> return 0;
>> --
>> 2.13.1.388.g69e6b9b4f4a9
