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?
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
