On Thu, Nov 10, 2016 at 12:46:18PM -0800, Song Liu wrote:
> With write cache, r5c_journal_mode is the knob to switch between
> write-back and write-through.
I'd prefer the name is journal_mode
> Below is an example:
>
> root@virt-test:~/# cat /sys/block/md0/md/r5c_state
> [write-through] write-back
> root@virt-test:~/# echo write-back > /sys/block/md0/md/r5c_state
> root@virt-test:~/# cat /sys/block/md0/md/r5c_state
this doesn't match the code, please update
> write-through [write-back]
>
> Signed-off-by: Song Liu <songliubraving@xxxxxx>
> ---
> drivers/md/raid5-cache.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++++
> drivers/md/raid5.c | 1 +
> drivers/md/raid5.h | 1 +
> 3 files changed, 62 insertions(+)
>
> diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c
> index 8330053..d2acb69 100644
> --- a/drivers/md/raid5-cache.c
> +++ b/drivers/md/raid5-cache.c
> @@ -60,6 +60,8 @@ enum r5c_journal_mode {
> R5C_JOURNAL_MODE_WRITE_BACK = 1,
> };
>
> +static char *r5c_journal_mode_str[] = {"write-through",
> + "write-back"};
> /*
> * raid5 cache state machine
> *
> @@ -1602,6 +1604,64 @@ static void r5l_write_super(struct r5l_log *log, sector_t cp)
> set_bit(MD_CHANGE_DEVS, &mddev->flags);
> }
>
> +static ssize_t r5c_journal_mode_show(struct mddev *mddev, char *page)
> +{
> + struct r5conf *conf = mddev->private;
> + int ret;
> +
> + if (!conf->log)
> + return 0;
> +
> + switch (conf->log->r5c_journal_mode) {
> + case R5C_JOURNAL_MODE_WRITE_THROUGH:
> + ret = snprintf(page, PAGE_SIZE, "[%s] %s\n",
> + r5c_journal_mode_str[R5C_JOURNAL_MODE_WRITE_THROUGH],
> + r5c_journal_mode_str[R5C_JOURNAL_MODE_WRITE_BACK]);
Limiting these lines within 80 character width doesn't impact readability
> + break;
> + case R5C_JOURNAL_MODE_WRITE_BACK:
> + ret = snprintf(page, PAGE_SIZE, "%s [%s]\n",
> + r5c_journal_mode_str[R5C_JOURNAL_MODE_WRITE_THROUGH],
> + r5c_journal_mode_str[R5C_JOURNAL_MODE_WRITE_BACK]);
> + break;
> + default:
> + ret = 0;
> + }
> + return ret;
> +}
> +
> +static ssize_t r5c_journal_mode_store(struct mddev *mddev,
> + const char *page, size_t len)
> +{
> + struct r5conf *conf = mddev->private;
> + struct r5l_log *log = conf->log;
> + int val = -1, i;
> +
> + if (!log)
> + return -ENODEV;
> +
> + for (i = 0; i < sizeof(r5c_journal_mode_str) / sizeof(r5c_journal_mode_str[0]); i++)
use ARRAY_SIZE
Thanks,
Shaohua
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