Re: [PATCH 8/9] f2fs: avoid race for summary information

From: Namjae Jeon
Date: Wed Apr 03 2013 - 01:54:17 EST


2013/4/1, Jaegeuk Kim <jaegeuk.kim@xxxxxxxxxxx>:
> In order to do GC more reliably, I'd like to lock the vicitm summary page
> until its GC is completed, and also prevent any checkpoint process.
>
> Signed-off-by: Jaegeuk Kim <jaegeuk.kim@xxxxxxxxxxx>
> ---
> fs/f2fs/gc.c | 8 +-------
> fs/f2fs/node.c | 2 +-
> fs/f2fs/super.c | 7 +++++--
> 3 files changed, 7 insertions(+), 10 deletions(-)
>
> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
> index 54aceb2..54ac13d 100644
> --- a/fs/f2fs/gc.c
> +++ b/fs/f2fs/gc.c
> @@ -641,12 +641,6 @@ static void do_garbage_collect(struct f2fs_sb_info
> *sbi, unsigned int segno,
> if (IS_ERR(sum_page))
> return;
>
> - /*
> - * CP needs to lock sum_page. In this time, we don't need
> - * to lock this page, because this summary page is not gone anywhere.
> - * Also, this page is not gonna be updated before GC is done.
> - */
> - unlock_page(sum_page);
> sum = page_address(sum_page);
>
> switch (GET_SUM_TYPE((&sum->footer))) {
> @@ -660,7 +654,7 @@ static void do_garbage_collect(struct f2fs_sb_info *sbi,
> unsigned int segno,
> stat_inc_seg_count(sbi, GET_SUM_TYPE((&sum->footer)));
> stat_inc_call_count(sbi->stat_info);
>
> - f2fs_put_page(sum_page, 0);
> + f2fs_put_page(sum_page, 1);
> }
>
> int f2fs_gc(struct f2fs_sb_info *sbi)
> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
> index c5360b7..7555fb7 100644
> --- a/fs/f2fs/node.c
> +++ b/fs/f2fs/node.c
> @@ -1148,7 +1148,7 @@ static int f2fs_write_node_pages(struct address_space
> *mapping,
>
> /* First check balancing cached NAT entries */
> if (try_to_free_nats(sbi, NAT_ENTRY_PER_BLOCK)) {
> - write_checkpoint(sbi, false);
> + f2fs_sync_fs(sbi->sb, true);
> return 0;
> }
>
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> index ea325c8..161e6c6 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -137,10 +137,13 @@ int f2fs_sync_fs(struct super_block *sb, int sync)
> if (!sbi->s_dirty && !get_pages(sbi, F2FS_DIRTY_NODES))
> return 0;
>
> - if (sync)
> + if (sync) {
> + mutex_lock(&sbi->gc_mutex);
> write_checkpoint(sbi, false);
> - else
> + mutex_unlock(&sbi->gc_mutex);
> + } else {
> f2fs_balance_fs(sbi);
> + }
We can remove { } of else because single line code is used.
Reviewed-by: Namjae Jeon <namjae.jeon@xxxxxxxxxxx>

Thanks.
>
> return 0;
> }
> --
> 1.8.1.3.566.gaa39828
>
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