diff options
| -rw-r--r-- | Documentation/md.txt | 9 | ||||
| -rw-r--r-- | drivers/md/md.c | 54 |
2 files changed, 61 insertions, 2 deletions
diff --git a/Documentation/md.txt b/Documentation/md.txt index 03a13c462cf..b19978e035f 100644 --- a/Documentation/md.txt +++ b/Documentation/md.txt @@ -207,6 +207,15 @@ All md devices contain: available. It will then appear at md/dev-XXX (depending on the name of the device) and further configuration is then possible. + safe_mode_delay + When an md array has seen no write requests for a certain period + of time, it will be marked as 'clean'. When another write + request arrive, the array is marked as 'dirty' before the write + commenses. This is known as 'safe_mode'. + The 'certain period' is controlled by this file which stores the + period as a number of seconds. The default is 200msec (0.200). + Writing a value of 0 disables safemode. + sync_speed_min sync_speed_max This are similar to /proc/sys/dev/raid/speed_limit_{min,max} diff --git a/drivers/md/md.c b/drivers/md/md.c index 30a93d64921..ad576ad2ca7 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -44,6 +44,7 @@ #include <linux/suspend.h> #include <linux/poll.h> #include <linux/mutex.h> +#include <linux/ctype.h> #include <linux/init.h> @@ -1978,6 +1979,54 @@ static void analyze_sbs(mddev_t * mddev) } static ssize_t +safe_delay_show(mddev_t *mddev, char *page) +{ + int msec = (mddev->safemode_delay*1000)/HZ; + return sprintf(page, "%d.%03d\n", msec/1000, msec%1000); +} +static ssize_t +safe_delay_store(mddev_t *mddev, const char *cbuf, size_t len) +{ + int scale=1; + int dot=0; + int i; + unsigned long msec; + char buf[30]; + char *e; + /* remove a period, and count digits after it */ + if (len >= sizeof(buf)) + return -EINVAL; + strlcpy(buf, cbuf, len); + buf[len] = 0; + for (i=0; i<len; i++) { + if (dot) { + if (isdigit(buf[i])) { + buf[i-1] = buf[i]; + scale *= 10; + } + buf[i] = 0; + } else if (buf[i] == '.') { + dot=1; + buf[i] = 0; + } + } + msec = simple_strtoul(buf, &e, 10); + if (e == buf || (*e && *e != '\n')) + return -EINVAL; + msec = (msec * 1000) / scale; + if (msec == 0) + mddev->safemode_delay = 0; + else { + mddev->safemode_delay = (msec*HZ)/1000; + if (mddev->safemode_delay == 0) + mddev->safemode_delay = 1; + } + return len; +} +static struct md_sysfs_entry md_safe_delay = +__ATTR(safe_mode_delay, 0644,safe_delay_show, safe_delay_store); + +static ssize_t level_show(mddev_t *mddev, char *page) { struct mdk_personality *p = mddev->pers; @@ -2433,6 +2482,7 @@ static struct attribute *md_default_attrs[] = { &md_size.attr, &md_metadata.attr, &md_new_device.attr, + &md_safe_delay.attr, NULL, }; @@ -2708,7 +2758,7 @@ static int do_md_run(mddev_t * mddev) mddev->safemode = 0; mddev->safemode_timer.function = md_safemode_timeout; mddev->safemode_timer.data = (unsigned long) mddev; - mddev->safemode_delay = (20 * HZ)/1000 +1; /* 20 msec delay */ + mddev->safemode_delay = (200 * HZ)/1000 +1; /* 200 msec delay */ mddev->in_sync = 1; ITERATE_RDEV(mddev,rdev,tmp) @@ -4594,7 +4644,7 @@ void md_write_end(mddev_t *mddev) if (atomic_dec_and_test(&mddev->writes_pending)) { if (mddev->safemode == 2) md_wakeup_thread(mddev->thread); - else + else if (mddev->safemode_delay) mod_timer(&mddev->safemode_timer, jiffies + mddev->safemode_delay); } } |