From 13de227bcd80fbdaeebe1f31154487dddb7d5b1e Mon Sep 17 00:00:00 2001 From: Holger Smolinski Date: Fri, 9 Jan 2009 12:14:51 +0100 Subject: [PATCH] [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 --- arch/s390/include/asm/dasd.h | 1 + drivers/s390/block/dasd_devmap.c | 48 ++++++++++++++++++++++++++++++++++++++++ drivers/s390/block/dasd_diag.c | 3 ++- drivers/s390/block/dasd_eckd.c | 3 ++- drivers/s390/block/dasd_fba.c | 3 ++- 5 files changed, 55 insertions(+), 3 deletions(-) diff --git a/arch/s390/include/asm/dasd.h b/arch/s390/include/asm/dasd.h index 55b2b80..fb50a78 100644 --- a/arch/s390/include/asm/dasd.h +++ b/arch/s390/include/asm/dasd.h @@ -78,6 +78,7 @@ typedef struct dasd_information2_t { #define DASD_FEATURE_USEDIAG 0x02 #define DASD_FEATURE_INITIAL_ONLINE 0x04 #define DASD_FEATURE_ERPLOG 0x08 +#define DASD_FEATURE_FAILFAST 0x10 #define DASD_PARTN_BITS 2 diff --git a/drivers/s390/block/dasd_devmap.c b/drivers/s390/block/dasd_devmap.c index 2ef2573..300e28a 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, " @@ -667,6 +669,51 @@ dasd_device_from_cdev(struct ccw_device *cdev) */ /* + * 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 */ static ssize_t @@ -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, }; diff --git a/drivers/s390/block/dasd_diag.c b/drivers/s390/block/dasd_diag.c index 7844461..ef2a569 100644 --- a/drivers/s390/block/dasd_diag.c +++ b/drivers/s390/block/dasd_diag.c @@ -544,7 +544,8 @@ static struct dasd_ccw_req *dasd_diag_build_cp(struct dasd_device *memdev, } cqr->retries = DIAG_MAX_RETRIES; cqr->buildclk = get_clock(); - if (blk_noretry_request(req)) + if (blk_noretry_request(req) || + block->base->features & DASD_FEATURE_FAILFAST) set_bit(DASD_CQR_FLAGS_FAILFAST, &cqr->flags); cqr->startdev = memdev; cqr->memdev = memdev; diff --git a/drivers/s390/block/dasd_eckd.c b/drivers/s390/block/dasd_eckd.c index bd2c52e..bdb8799 100644 --- a/drivers/s390/block/dasd_eckd.c +++ b/drivers/s390/block/dasd_eckd.c @@ -1700,7 +1700,8 @@ static struct dasd_ccw_req *dasd_eckd_build_cp(struct dasd_device *startdev, recid++; } } - if (blk_noretry_request(req)) + if (blk_noretry_request(req) || + block->base->features & DASD_FEATURE_FAILFAST) set_bit(DASD_CQR_FLAGS_FAILFAST, &cqr->flags); cqr->startdev = startdev; cqr->memdev = startdev; diff --git a/drivers/s390/block/dasd_fba.c b/drivers/s390/block/dasd_fba.c index 7d442ae..f1d17602 100644 --- a/drivers/s390/block/dasd_fba.c +++ b/drivers/s390/block/dasd_fba.c @@ -355,7 +355,8 @@ static struct dasd_ccw_req *dasd_fba_build_cp(struct dasd_device * memdev, recid++; } } - if (blk_noretry_request(req)) + if (blk_noretry_request(req) || + block->base->features & DASD_FEATURE_FAILFAST) set_bit(DASD_CQR_FLAGS_FAILFAST, &cqr->flags); cqr->startdev = memdev; cqr->memdev = memdev; -- 2.7.4