From 13de227bcd80fbdaeebe1f31154487dddb7d5b1e Mon Sep 17 00:00:00 2001 From: Holger Smolinski Date: Fri, 9 Jan 2009 12:14:51 +0100 Subject: [S390] dasd: add device attribute to disable blocking on lost paths When the connection between host and storage server is lost, the dasd device driver usually blocks all I/O on affected devices and waits for them to reappear. In some setups however it would be better if the I/O is returned as error so that device can be recovered by some other means, eg. in a raid or multipath setup. Signed-off-by: Holger Smolinski Signed-off-by: Stefan Weinhuber Signed-off-by: Martin Schwidefsky --- drivers/s390/block/dasd_devmap.c | 48 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+) (limited to 'drivers/s390/block/dasd_devmap.c') diff --git a/drivers/s390/block/dasd_devmap.c b/drivers/s390/block/dasd_devmap.c index 2ef25731d19..300e28a531f 100644 --- a/drivers/s390/block/dasd_devmap.c +++ b/drivers/s390/block/dasd_devmap.c @@ -206,6 +206,8 @@ dasd_feature_list(char *str, char **endp) features |= DASD_FEATURE_USEDIAG; else if (len == 6 && !strncmp(str, "erplog", 6)) features |= DASD_FEATURE_ERPLOG; + else if (len == 8 && !strncmp(str, "failfast", 8)) + features |= DASD_FEATURE_FAILFAST; else { MESSAGE(KERN_WARNING, "unsupported feature: %*s, " @@ -666,6 +668,51 @@ dasd_device_from_cdev(struct ccw_device *cdev) * SECTION: files in sysfs */ +/* + * failfast controls the behaviour, if no path is available + */ +static ssize_t dasd_ff_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct dasd_devmap *devmap; + int ff_flag; + + devmap = dasd_find_busid(dev->bus_id); + if (!IS_ERR(devmap)) + ff_flag = (devmap->features & DASD_FEATURE_FAILFAST) != 0; + else + ff_flag = (DASD_FEATURE_DEFAULT & DASD_FEATURE_FAILFAST) != 0; + return snprintf(buf, PAGE_SIZE, ff_flag ? "1\n" : "0\n"); +} + +static ssize_t dasd_ff_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + struct dasd_devmap *devmap; + int val; + char *endp; + + devmap = dasd_devmap_from_cdev(to_ccwdev(dev)); + if (IS_ERR(devmap)) + return PTR_ERR(devmap); + + val = simple_strtoul(buf, &endp, 0); + if (((endp + 1) < (buf + count)) || (val > 1)) + return -EINVAL; + + spin_lock(&dasd_devmap_lock); + if (val) + devmap->features |= DASD_FEATURE_FAILFAST; + else + devmap->features &= ~DASD_FEATURE_FAILFAST; + if (devmap->device) + devmap->device->features = devmap->features; + spin_unlock(&dasd_devmap_lock); + return count; +} + +static DEVICE_ATTR(failfast, 0644, dasd_ff_show, dasd_ff_store); + /* * readonly controls the readonly status of a dasd */ @@ -1020,6 +1067,7 @@ static struct attribute * dasd_attrs[] = { &dev_attr_use_diag.attr, &dev_attr_eer_enabled.attr, &dev_attr_erplog.attr, + &dev_attr_failfast.attr, NULL, }; -- cgit v1.2.3