diff options
| author | Heinz Mauelshagen <heinzm@redhat.com> | 2017-03-22 17:44:37 +0100 |
|---|---|---|
| committer | Mike Snitzer <snitzer@redhat.com> | 2017-03-27 11:13:47 -0400 |
| commit | 78e470c26f524f4706c2555613b9641d85190cbe (patch) | |
| tree | dfc665acd9116cb93a2c11809758c13352950b62 /drivers/md/raid5-cache.c | |
| parent | ff3af92b4461be773337111daea80bb91b2cd545 (diff) | |
md: add raid4/5/6 journal mode switching API
Commit 2ded370373a4 ("md/r5cache: State machine for raid5-cache write
back mode") added support for "write-back" caching on the raid journal
device.
In order to allow the dm-raid target to switch between the available
"write-through" and "write-back" modes, provide a new
r5c_journal_mode_set() API.
Use the new API in existing r5c_journal_mode_store()
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Acked-by: Shaohua Li <shli@fb.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md/raid5-cache.c')
| -rw-r--r-- | drivers/md/raid5-cache.c | 62 |
1 files changed, 34 insertions, 28 deletions
diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c index 3f307be01b10..218b6f37da85 100644 --- a/drivers/md/raid5-cache.c +++ b/drivers/md/raid5-cache.c @@ -53,16 +53,6 @@ */ #define R5L_POOL_SIZE 4 -/* - * r5c journal modes of the array: write-back or write-through. - * write-through mode has identical behavior as existing log only - * implementation. - */ -enum r5c_journal_mode { - R5C_JOURNAL_MODE_WRITE_THROUGH = 0, - R5C_JOURNAL_MODE_WRITE_BACK = 1, -}; - static char *r5c_journal_mode_str[] = {"write-through", "write-back"}; /* @@ -2327,40 +2317,56 @@ static ssize_t r5c_journal_mode_show(struct mddev *mddev, char *page) return ret; } -static ssize_t r5c_journal_mode_store(struct mddev *mddev, - const char *page, size_t length) +/* + * Set journal cache mode on @mddev (external API initially needed by dm-raid). + * + * @mode as defined in 'enum r5c_journal_mode'. + * + */ +int r5c_journal_mode_set(struct mddev *mddev, int mode) { struct r5conf *conf = mddev->private; struct r5l_log *log = conf->log; - int val = -1, i; - int len = length; if (!log) return -ENODEV; - if (len && page[len - 1] == '\n') - len -= 1; - for (i = 0; i < ARRAY_SIZE(r5c_journal_mode_str); i++) - if (strlen(r5c_journal_mode_str[i]) == len && - strncmp(page, r5c_journal_mode_str[i], len) == 0) { - val = i; - break; - } - if (val < R5C_JOURNAL_MODE_WRITE_THROUGH || - val > R5C_JOURNAL_MODE_WRITE_BACK) + if (mode < R5C_JOURNAL_MODE_WRITE_THROUGH || + mode > R5C_JOURNAL_MODE_WRITE_BACK) return -EINVAL; if (raid5_calc_degraded(conf) > 0 && - val == R5C_JOURNAL_MODE_WRITE_BACK) + mode == R5C_JOURNAL_MODE_WRITE_BACK) return -EINVAL; mddev_suspend(mddev); - conf->log->r5c_journal_mode = val; + conf->log->r5c_journal_mode = mode; mddev_resume(mddev); pr_debug("md/raid:%s: setting r5c cache mode to %d: %s\n", - mdname(mddev), val, r5c_journal_mode_str[val]); - return length; + mdname(mddev), mode, r5c_journal_mode_str[mode]); + return 0; +} +EXPORT_SYMBOL(r5c_journal_mode_set); + +static ssize_t r5c_journal_mode_store(struct mddev *mddev, + const char *page, size_t length) +{ + int mode = ARRAY_SIZE(r5c_journal_mode_str); + size_t len = length; + + if (len < 2) + return -EINVAL; + + if (page[len - 1] == '\n') + len--; + + while (mode--) + if (strlen(r5c_journal_mode_str[mode]) == len && + !strncmp(page, r5c_journal_mode_str[mode], len)) + break; + + return r5c_journal_mode_set(mddev, mode) ?: length; } struct md_sysfs_entry |