---

yaml
---
r: 176095
b: refs/heads/master
c: 1e50915
h: refs/heads/master
i:
  176093: b88f125
  176091: 8378346
  176087: 61b8685
  176079: 8161e60
  176063: 08cf4db
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 67b8dc4b06b0e97df55fd76e209f34f9a52e820e
+refs/heads/master: 1e50915fe0bbf7a46db0fa7e1e604d3fc95f057d

trunk/drivers/md/md.c

@@ -67,6 +67,12 @@ static DECLARE_WAIT_QUEUE_HEAD(resync_wait);
 
 #define MD_BUG(x...) { printk("md: bug in file %s, line %d\n", __FILE__, __LINE__); md_print_devices(); }
 
+/*
+ * Default number of read corrections we'll attempt on an rdev
+ * before ejecting it from the array. We divide the read error
+ * count by 2 for every hour elapsed between read errors.
+ */
+#define MD_DEFAULT_MAX_CORRECTED_READ_ERRORS 20
 /*
  * Current RAID-1,4,5 parallel reconstruction 'guaranteed speed limit'
  * is 1000 KB/sec, so the extra system load does not show up that much.
@@ -2653,6 +2659,8 @@ static mdk_rdev_t *md_import_device(dev_t newdev, int super_format, int super_mi
 	rdev->flags = 0;
 	rdev->data_offset = 0;
 	rdev->sb_events = 0;
+	rdev->last_read_error.tv_sec  = 0;
+	rdev->last_read_error.tv_nsec = 0;
 	atomic_set(&rdev->nr_pending, 0);
 	atomic_set(&rdev->read_errors, 0);
 	atomic_set(&rdev->corrected_errors, 0);
@@ -3289,6 +3297,29 @@ array_state_store(mddev_t *mddev, const char *buf, size_t len)
 static struct md_sysfs_entry md_array_state =
 __ATTR(array_state, S_IRUGO|S_IWUSR, array_state_show, array_state_store);
 
+static ssize_t
+max_corrected_read_errors_show(mddev_t *mddev, char *page) {
+	return sprintf(page, "%d\n",
+		       atomic_read(&mddev->max_corr_read_errors));
+}
+
+static ssize_t
+max_corrected_read_errors_store(mddev_t *mddev, const char *buf, size_t len)
+{
+	char *e;
+	unsigned long n = simple_strtoul(buf, &e, 10);
+
+	if (*buf && (*e == 0 || *e == '\n')) {
+		atomic_set(&mddev->max_corr_read_errors, n);
+		return len;
+	}
+	return -EINVAL;
+}
+
+static struct md_sysfs_entry max_corr_read_errors =
+__ATTR(max_read_errors, S_IRUGO|S_IWUSR, max_corrected_read_errors_show,
+	max_corrected_read_errors_store);
+
 static ssize_t
 null_show(mddev_t *mddev, char *page)
 {
@@ -3914,6 +3945,7 @@ static struct attribute *md_default_attrs[] = {
 	&md_array_state.attr,
 	&md_reshape_position.attr,
 	&md_array_size.attr,
+	&max_corr_read_errors.attr,
 	NULL,
 };
 
@@ -4333,6 +4365,8 @@ static int do_md_run(mddev_t * mddev)
 		mddev->ro = 0;
 
  	atomic_set(&mddev->writes_pending,0);
+	atomic_set(&mddev->max_corr_read_errors,
+		   MD_DEFAULT_MAX_CORRECTED_READ_ERRORS);
 	mddev->safemode = 0;
 	mddev->safemode_timer.function = md_safemode_timeout;
 	mddev->safemode_timer.data = (unsigned long) mddev;

trunk/drivers/md/md.h

@@ -97,6 +97,9 @@ struct mdk_rdev_s
 	atomic_t	read_errors;	/* number of consecutive read errors that
 					 * we have tried to ignore.
 					 */
+	struct timespec last_read_error;	/* monotonic time since our
+						 * last read error
+						 */
 	atomic_t	corrected_errors; /* number of corrected read errors,
 					   * for reporting to userspace and storing
 					   * in superblock.
@@ -299,6 +302,7 @@ struct mddev_s
 		int			external;
 	} bitmap_info;
 
+	atomic_t 			max_corr_read_errors; /* max read retries */
 	struct list_head		all_mddevs;
 
 	/* Generic barrier handling.

trunk/drivers/md/raid10.c

@@ -1431,6 +1431,43 @@ static void recovery_request_write(mddev_t *mddev, r10bio_t *r10_bio)
 }
 
 
+/*
+ * Used by fix_read_error() to decay the per rdev read_errors.
+ * We halve the read error count for every hour that has elapsed
+ * since the last recorded read error.
+ *
+ */
+static void check_decay_read_errors(mddev_t *mddev, mdk_rdev_t *rdev)
+{
+	struct timespec cur_time_mon;
+	unsigned long hours_since_last;
+	unsigned int read_errors = atomic_read(&rdev->read_errors);
+
+	ktime_get_ts(&cur_time_mon);
+
+	if (rdev->last_read_error.tv_sec == 0 &&
+	    rdev->last_read_error.tv_nsec == 0) {
+		/* first time we've seen a read error */
+		rdev->last_read_error = cur_time_mon;
+		return;
+	}
+
+	hours_since_last = (cur_time_mon.tv_sec -
+			    rdev->last_read_error.tv_sec) / 3600;
+
+	rdev->last_read_error = cur_time_mon;
+
+	/*
+	 * if hours_since_last is > the number of bits in read_errors
+	 * just set read errors to 0. We do this to avoid
+	 * overflowing the shift of read_errors by hours_since_last.
+	 */
+	if (hours_since_last >= 8 * sizeof(read_errors))
+		atomic_set(&rdev->read_errors, 0);
+	else
+		atomic_set(&rdev->read_errors, read_errors >> hours_since_last);
+}
+
 /*
  * This is a kernel thread which:
  *
@@ -1444,6 +1481,43 @@ static void fix_read_error(conf_t *conf, mddev_t *mddev, r10bio_t *r10_bio)
 	int sect = 0; /* Offset from r10_bio->sector */
 	int sectors = r10_bio->sectors;
 	mdk_rdev_t*rdev;
+	int max_read_errors = atomic_read(&mddev->max_corr_read_errors);
+
+	rcu_read_lock();
+	{
+		int d = r10_bio->devs[r10_bio->read_slot].devnum;
+		char b[BDEVNAME_SIZE];
+		int cur_read_error_count = 0;
+
+		rdev = rcu_dereference(conf->mirrors[d].rdev);
+		bdevname(rdev->bdev, b);
+
+		if (test_bit(Faulty, &rdev->flags)) {
+			rcu_read_unlock();
+			/* drive has already been failed, just ignore any
+			   more fix_read_error() attempts */
+			return;
+		}
+
+		check_decay_read_errors(mddev, rdev);
+		atomic_inc(&rdev->read_errors);
+		cur_read_error_count = atomic_read(&rdev->read_errors);
+		if (cur_read_error_count > max_read_errors) {
+			rcu_read_unlock();
+			printk(KERN_NOTICE
+			       "raid10: %s: Raid device exceeded "
+			       "read_error threshold "
+			       "[cur %d:max %d]\n",
+			       b, cur_read_error_count, max_read_errors);
+			printk(KERN_NOTICE
+			       "raid10: %s: Failing raid "
+			       "device\n", b);
+			md_error(mddev, conf->mirrors[d].rdev);
+			return;
+		}
+	}
+	rcu_read_unlock();
+
 	while(sectors) {
 		int s = sectors;
 		int sl = r10_bio->read_slot;