summaryrefslogtreecommitdiff
path: root/fs/xfs/xfs_sysfs.c
diff options
context:
space:
mode:
authorBrian Foster <bfoster@redhat.com>2016-01-05 07:41:16 +1100
committerDave Chinner <david@fromorbit.com>2016-01-05 07:41:16 +1100
commit609adfc2ed5ba16700f125da0b656248bd9d4316 (patch)
tree6612e2f6a7d93cfeeb806abe25def385943544d3 /fs/xfs/xfs_sysfs.c
parent7088c4136fa1cba26531fde40bdcfcf3d2ccd533 (diff)
xfs: debug mode log record crc error injection
XFS now uses CRC verification over a limited section of the log to detect torn writes prior to a crash. This is difficult to test directly due to the timing and hardware requirements to cause a short write. Add a mechanism to inject CRC errors into log records to facilitate testing torn write detection during log recovery. This mechanism is dangerous and can result in filesystem corruption. Thus, it is only available in DEBUG mode for testing/development purposes. Set a non-zero value to the following sysfs entry to enable error injection: /sys/fs/xfs/<dev>/log/log_badcrc_factor Once enabled, XFS intentionally writes an invalid CRC to a log record at some random point in the future based on the provided frequency. The filesystem immediately shuts down once the record has been written to the physical log to prevent metadata writeback (e.g., AIL insertion) once the log write completes. This helps reasonably simulate a torn write to the log as the affected record must be safe to discard. The next mount after the intentional shutdown requires log recovery and should detect and recover from the torn write. Note again that this _will_ result in data loss or worse. For testing and development purposes only! Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
Diffstat (limited to 'fs/xfs/xfs_sysfs.c')
-rw-r--r--fs/xfs/xfs_sysfs.c36
1 files changed, 36 insertions, 0 deletions
diff --git a/fs/xfs/xfs_sysfs.c b/fs/xfs/xfs_sysfs.c
index ee70f5dec9dc..641d625eb334 100644
--- a/fs/xfs/xfs_sysfs.c
+++ b/fs/xfs/xfs_sysfs.c
@@ -255,11 +255,47 @@ write_grant_head_show(
}
XFS_SYSFS_ATTR_RO(write_grant_head);
+#ifdef DEBUG
+STATIC ssize_t
+log_badcrc_factor_store(
+ struct kobject *kobject,
+ const char *buf,
+ size_t count)
+{
+ struct xlog *log = to_xlog(kobject);
+ int ret;
+ uint32_t val;
+
+ ret = kstrtouint(buf, 0, &val);
+ if (ret)
+ return ret;
+
+ log->l_badcrc_factor = val;
+
+ return count;
+}
+
+STATIC ssize_t
+log_badcrc_factor_show(
+ struct kobject *kobject,
+ char *buf)
+{
+ struct xlog *log = to_xlog(kobject);
+
+ return snprintf(buf, PAGE_SIZE, "%d\n", log->l_badcrc_factor);
+}
+
+XFS_SYSFS_ATTR_RW(log_badcrc_factor);
+#endif /* DEBUG */
+
static struct attribute *xfs_log_attrs[] = {
ATTR_LIST(log_head_lsn),
ATTR_LIST(log_tail_lsn),
ATTR_LIST(reserve_grant_head),
ATTR_LIST(write_grant_head),
+#ifdef DEBUG
+ ATTR_LIST(log_badcrc_factor),
+#endif
NULL,
};