On Sun, 19 Jul 2009 14:26:22 +0900, Jiro SEKIBA wrote:
> This patch makes commiting super block in nilfs internal thread,
> instead of periodic write_super callback.
>
> VFS layer calls ->write_super callback periodically. However,
> it looks like that calling back is ommited when disk I/O is busy.
> And when cleanerd (nilfs GC) is runnig, disk I/O tend to be busy thus
> nilfs superblock is not synchronized as nilfs designed.
>
> To avoid it, syncing superblock by nilfs thread instead of pdflush.
>
> Signed-off-by: Jiro SEKIBA <[email protected]>
Thanks.
If you replaced nilfs_write_super() in nilfs_sync_super(), you can get
rid of nilfs_write_super() in this patch including the comments and
prototype declaration for it.
Here are a few additional comments on that condition.
> ---
> fs/nilfs2/segment.c | 12 +++++++++++-
> fs/nilfs2/super.c | 2 +-
> 2 files changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c
> index 8b5e477..46f7a49 100644
> --- a/fs/nilfs2/segment.c
> +++ b/fs/nilfs2/segment.c
> @@ -2486,8 +2486,10 @@ static int nilfs_segctor_construct(struct
> nilfs_sc_info *sci,
> atomic_set(&nilfs->ns_ndirtyblks, 0);
> if (test_bit(NILFS_SC_SUPER_ROOT, &sci->sc_flags) &&
> nilfs_discontinued(nilfs)) {
> + u64 t = get_seconds();
> down_write(&nilfs->ns_sem);
> - req->sb_err = nilfs_commit_super(sbi, 0);
> + req->sb_err = nilfs_commit_super(sbi,
> + nilfs_altsb_need_update(nilfs, t));
> up_write(&nilfs->ns_sem);
You can hide get_seconds() inside nilfs_sb_need_update() and
nilfs_altsb_need_update() especially if you will get rid of
nilfs_write_super().
> }
> }
> @@ -2675,6 +2677,9 @@ static int nilfs_segctor_thread(void *arg)
> } else {
> DEFINE_WAIT(wait);
> int should_sleep = 1;
> + u64 t;
> + struct nilfs_sb_info *sbi;
> + struct the_nilfs *nilfs;
>
> prepare_to_wait(&sci->sc_wait_daemon, &wait,
> TASK_INTERRUPTIBLE);
> @@ -2695,6 +2700,11 @@ static int nilfs_segctor_thread(void *arg)
> finish_wait(&sci->sc_wait_daemon, &wait);
> timeout = ((sci->sc_state & NILFS_SEGCTOR_COMMIT) &&
> time_after_eq(jiffies, sci->sc_timer->expires));
> + t = get_seconds();
> + sbi = sci->sc_sbi;
> + nilfs = sbi->s_nilfs;
> + if (sci->sc_super->s_dirt && nilfs_sb_need_update(nilfs, t))
> + set_nilfs_discontinued(nilfs);
ditto.
And the sbi local variable seems omissible.
> }
> goto loop;
>
> diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c
> index d85b360..a8c5875 100644
> --- a/fs/nilfs2/super.c
> +++ b/fs/nilfs2/super.c
> @@ -534,7 +534,7 @@ static struct super_operations nilfs_sops = {
> /* .drop_inode = nilfs_drop_inode, */
> .delete_inode = nilfs_delete_inode,
> .put_super = nilfs_put_super,
> - .write_super = nilfs_write_super,
> + /* .write_super = nilfs_write_super, */
> .sync_fs = nilfs_sync_fs,
> /* .write_super_lockfs */
> /* .unlockfs */
> --
> 1.5.6.5
>
Thanks,
Ryusuke Konishi
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