md: make error_handler functions more uniform and correct.

- there is no need to test_bit Faulty, as that was already done in
  md_error which is the only caller of these functions.
- MD_CHANGE_DEVS should be set *after* faulty is set to ensure
  metadata is updated correctly.
- spinlock should be held while updating ->degraded.

Signed-off-by: NeilBrown <neilb@suse.de>

  

1 files changed, 22 insertions, 18 deletions

diff --git a/drivers/md/multipath.c b/drivers/md/multipath.c
index 02547124aa83..3535c23af288 100644
--- a/drivers/md/multipath.c
+++ b/drivers/md/multipath.c
@@ -186,6 +186,7 @@ static int multipath_congested(void *data, int bits)
 static void multipath_error (mddev_t *mddev, mdk_rdev_t *rdev)
 {
         multipath_conf_t *conf = mddev->private;
+        char b[BDEVNAME_SIZE];
 
         if (conf->raid_disks - mddev->degraded <= 1) {
                 /*
@@ -194,26 +195,27 @@ static void multipath_error (mddev_t *mddev, mdk_rdev_t *rdev)
                  * which has just failed.
                  */
                 printk(KERN_ALERT 
-                        "multipath: only one IO path left and IO error.\n");
+                       "multipath: only one IO path left and IO error.\n");
                 /* leave it active... it's all we have */
-        } else {
-                /*
-                 * Mark disk as unusable
-                 */
-                if (!test_bit(Faulty, &rdev->flags)) {
-                        char b[BDEVNAME_SIZE];
-                        clear_bit(In_sync, &rdev->flags);
-                        set_bit(Faulty, &rdev->flags);
-                        set_bit(MD_CHANGE_DEVS, &mddev->flags);
-                        mddev->degraded++;
-                        printk(KERN_ALERT "multipath: IO failure on %s,"
-                                " disabling IO path.\n"
-                                "multipath: Operation continuing"
-                                " on %d IO paths.\n",
-                                bdevname (rdev->bdev,b),
-                                conf->raid_disks - mddev->degraded);
-                }
+                return;
+        }
+        /*
+         * Mark disk as unusable
+         */
+        if (test_and_clear_bit(In_sync, &rdev->flags)) {
+                unsigned long flags;
+                spin_lock_irqsave(&conf->device_lock, flags);
+                mddev->degraded++;
+                spin_unlock_irqrestore(&conf->device_lock, flags);
         }
+        set_bit(Faulty, &rdev->flags);
+        set_bit(MD_CHANGE_DEVS, &mddev->flags);
+        printk(KERN_ALERT "multipath: IO failure on %s,"
+               " disabling IO path.\n"
+               "multipath: Operation continuing"
+               " on %d IO paths.\n",
+               bdevname(rdev->bdev, b),
+               conf->raid_disks - mddev->degraded);
 }
 
 static void print_multipath_conf (multipath_conf_t *conf)
@@ -273,9 +275,11 @@ static int multipath_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
                                                            PAGE_CACHE_SIZE - 1);
                         }
 
+                        spin_lock_irq(&conf->device_lock);
                         mddev->degraded--;
                         rdev->raid_disk = path;
                         set_bit(In_sync, &rdev->flags);
+                        spin_unlock_irq(&conf->device_lock);
                         rcu_assign_pointer(p->rdev, rdev);
                         err = 0;
                         md_integrity_add_rdev(rdev, mddev);