Hi Chao,
On Tue, Dec 15, 2015 at 01:33:18PM +0800, Chao Yu wrote:
> Previously, when finishing a checkpoint, we only keep consistency of all fs
> meta info including meta inode, node inode, dentry page of directory inode,
> so, after a sudden power cut, f2fs can recover from last checkpoint with
> full directory structure.
>
> But during checkpoint, we didn't flush dirty pages of regular and symlink
> inode, so such dirty datas still in memory will be lost in that moment of
> power off.
>
> In order to reduce the chance of lost data, this patch tries to flush user
> data before starting a checkpoint. So user's data written between two
> checkpoint which may not be fsynced could be saved.
>
> Signed-off-by: Chao Yu <chao2...@samsung.com>
> ---
> fs/f2fs/checkpoint.c | 11 +++++++++++
> fs/f2fs/f2fs.h | 5 +++++
> 2 files changed, 16 insertions(+)
>
> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
> index f33c4d7..217571f 100644
> --- a/fs/f2fs/checkpoint.c
> +++ b/fs/f2fs/checkpoint.c
> @@ -849,6 +849,17 @@ static int block_operations(struct f2fs_sb_info *sbi)
>
> blk_start_plug(&plug);
>
> +retry_flush_datas:
> + /* write all the dirty data pages */
> + if (get_pages(sbi, F2FS_DIRTY_DATAS)) {
> + sync_dirty_inodes(sbi, FILE_INODE);
> + if (unlikely(f2fs_cp_error(sbi))) {
> + err = -EIO;
> + goto out;
> + }
> + goto retry_flush_datas;
> + }
> +
Please don't do like this; our checkpoint should be different from system sync.
I don't want to increase the checkpoint latency at all even in f2fs_gc as well.
I think that something like this would be better.
In f2fs_balance_fs_bg(),
if (!avaliable_free_memory() || ...) {
if (test_opt(DATA_FLUSH))
sync_dirty_inodes(FILE_INODE);
f2fs_sync_fs();
}
Please add its mount option with a disabled one first.
> retry_flush_dents:
> f2fs_lock_all(sbi);
> /* write all the dirty dentry pages */
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index d8bef3c..2477b2f5 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -648,6 +648,7 @@ struct f2fs_sm_info {
> enum count_type {
> F2FS_WRITEBACK,
> F2FS_DIRTY_DENTS,
> + F2FS_DIRTY_DATAS,
This should be F2FS_DIRTY_DATA.
And, it'd better to merge this part into your previous patch:
"f2fs: record dirty status of regular/symlink inodes"
I'll do that, so please check it out later from dev-test.
> F2FS_DIRTY_NODES,
> F2FS_DIRTY_META,
> F2FS_INMEM_PAGES,
> @@ -1068,6 +1069,8 @@ static inline void inode_inc_dirty_pages(struct inode
> *inode)
> atomic_inc(&F2FS_I(inode)->dirty_pages);
> if (S_ISDIR(inode->i_mode))
> inc_page_count(F2FS_I_SB(inode), F2FS_DIRTY_DENTS);
> + else
> + inc_page_count(F2FS_I_SB(inode), F2FS_DIRTY_DATAS);
ditto.
> }
>
> static inline void dec_page_count(struct f2fs_sb_info *sbi, int count_type)
> @@ -1085,6 +1088,8 @@ static inline void inode_dec_dirty_pages(struct inode
> *inode)
>
> if (S_ISDIR(inode->i_mode))
> dec_page_count(F2FS_I_SB(inode), F2FS_DIRTY_DENTS);
> + else
> + dec_page_count(F2FS_I_SB(inode), F2FS_DIRTY_DATAS);
ditto.
> }
>
> static inline int get_pages(struct f2fs_sb_info *sbi, int count_type)
> --
> 2.6.3
>
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