Make sure all changes to md/dev-XX/state are notified

The important state change happens during an interrupt
in md_error.  So just set a flag there and call sysfs_notify
later in process context.

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

3 files changed, 26 insertions, 1 deletions

diff --git a/Documentation/md.txt b/Documentation/md.txt
index eb6e69e3732e..e06cc59437e4 100644
--- a/Documentation/md.txt
+++ b/Documentation/md.txt
@@ -297,6 +297,10 @@ Each directory contains:
               writemostly - device will only be subject to read
                          requests if there are no other options.
                          This applies only to raid1 arrays.
+              blocked  - device has failed, metadata is "external",
+                         and the failure hasn't been acknowledged yet.
+                         Writes that would write to this device if
+                         it were not faulty are blocked.
               spare    - device is working, but not a full member.
                          This includes spares that are in the process
                          of being recovered to
@@ -306,6 +310,12 @@ Each directory contains:
         Writing "remove" removes the device from the array.
         Writing "writemostly" sets the writemostly flag.
         Writing "-writemostly" clears the writemostly flag.
+        Writing "blocked" sets the "blocked" flag.
+        Writing "-blocked" clear the "blocked" flag and allows writes
+                to complete.
+
+        This file responds to select/poll. Any change to 'faulty'
+        or 'blocked' causes an event.
 
       errors
         An approximate count of read errors that have been detected on
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 60d4cad88c20..dc99d95a1b6d 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -1886,6 +1886,8 @@ state_store(mdk_rdev_t *rdev, const char *buf, size_t len)
 
                 err = 0;
         }
+        if (!err)
+                sysfs_notify(&rdev->kobj, NULL, "state");
         return err ? err : len;
 }
 static struct rdev_sysfs_entry rdev_state =
@@ -1979,7 +1981,8 @@ slot_store(mdk_rdev_t *rdev, const char *buf, size_t len)
                 if (err) {
                         rdev->raid_disk = -1;
                         return err;
-                }
+                } else
+                        sysfs_notify(&rdev->kobj, NULL, "state");
                 sprintf(nm, "rd%d", rdev->raid_disk);
                 if (sysfs_create_link(&rdev->mddev->kobj, &rdev->kobj, nm))
                         printk(KERN_WARNING
@@ -1996,6 +1999,7 @@ slot_store(mdk_rdev_t *rdev, const char *buf, size_t len)
                 clear_bit(Faulty, &rdev->flags);
                 clear_bit(WriteMostly, &rdev->flags);
                 set_bit(In_sync, &rdev->flags);
+                sysfs_notify(&rdev->kobj, NULL, "state");
         }
         return len;
 }
@@ -3525,6 +3529,7 @@ static int do_md_run(mddev_t * mddev)
                                 return -EINVAL;
                         }
                 }
+                sysfs_notify(&rdev->kobj, NULL, "state");
         }
 
         md_probe(mddev->unit, NULL, NULL);
@@ -4256,6 +4261,8 @@ static int add_new_disk(mddev_t * mddev, mdu_disk_info_t *info)
                 }
                 if (err)
                         export_rdev(rdev);
+                else
+                        sysfs_notify(&rdev->kobj, NULL, "state");
 
                 md_update_sb(mddev, 1);
                 if (mddev->degraded)
@@ -5115,6 +5122,7 @@ void md_error(mddev_t *mddev, mdk_rdev_t *rdev)
         mddev->pers->error_handler(mddev,rdev);
         if (mddev->degraded)
                 set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
+        set_bit(StateChanged, &rdev->flags);
         set_bit(MD_RECOVERY_INTR, &mddev->recovery);
         set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
         md_wakeup_thread(mddev->thread);
@@ -6037,6 +6045,10 @@ void md_check_recovery(mddev_t *mddev)
                 if (mddev->flags)
                         md_update_sb(mddev, 0);
 
+                rdev_for_each(rdev, rtmp, mddev)
+                        if (test_and_clear_bit(StateChanged, &rdev->flags))
+                                sysfs_notify(&rdev->kobj, NULL, "state");
+
 
                 if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) &&
                     !test_bit(MD_RECOVERY_DONE, &mddev->recovery)) {
diff --git a/include/linux/raid/md_k.h b/include/linux/raid/md_k.h
index 62aa9c9a6ddc..df30c4395875 100644
--- a/include/linux/raid/md_k.h
+++ b/include/linux/raid/md_k.h
@@ -87,6 +87,9 @@ struct mdk_rdev_s
 #define Blocked         8               /* An error occured on an externally
                                          * managed array, don't allow writes
                                          * until it is cleared */
+#define StateChanged    9               /* Faulty or Blocked has changed during
+                                         * interrupt, so it needs to be
+                                         * notified by the thread */
         wait_queue_head_t blocked_wait;
 
         int desc_nr;                    /* descriptor index in the superblock */