Merge branch 'for-linus' of git://neil.brown.name/md

* 'for-linus' of git://neil.brown.name/md:
  Fix problem with waiting while holding rcu read lock in md/bitmap.c
  Remove invalidate_partition call from do_md_stop.

diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index 7e65bad522cb26456b4b1909d69b7c72e52efb3d..ac89a5deaca2e12fa62ccb78f1d62b088039675c 100644 (file)
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -238,15 +238,47 @@ static struct page *read_sb_page(mddev_t *mddev, long offset, unsigned long inde
 
 }
 
+static mdk_rdev_t *next_active_rdev(mdk_rdev_t *rdev, mddev_t *mddev)
+{
+       /* Iterate the disks of an mddev, using rcu to protect access to the
+        * linked list, and raising the refcount of devices we return to ensure
+        * they don't disappear while in use.
+        * As devices are only added or removed when raid_disk is < 0 and
+        * nr_pending is 0 and In_sync is clear, the entries we return will
+        * still be in the same position on the list when we re-enter
+        * list_for_each_continue_rcu.
+        */
+       struct list_head *pos;
+       rcu_read_lock();
+       if (rdev == NULL)
+               /* start at the beginning */
+               pos = &mddev->disks;
+       else {
+               /* release the previous rdev and start from there. */
+               rdev_dec_pending(rdev, mddev);
+               pos = &rdev->same_set;
+       }
+       list_for_each_continue_rcu(pos, &mddev->disks) {
+               rdev = list_entry(pos, mdk_rdev_t, same_set);
+               if (rdev->raid_disk >= 0 &&
+                   test_bit(In_sync, &rdev->flags) &&
+                   !test_bit(Faulty, &rdev->flags)) {
+                       /* this is a usable devices */
+                       atomic_inc(&rdev->nr_pending);
+                       rcu_read_unlock();
+                       return rdev;
+               }
+       }
+       rcu_read_unlock();
+       return NULL;
+}
+
 static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
 {
-       mdk_rdev_t *rdev;
+       mdk_rdev_t *rdev = NULL;
        mddev_t *mddev = bitmap->mddev;
 
-       rcu_read_lock();
-       rdev_for_each_rcu(rdev, mddev)
-               if (test_bit(In_sync, &rdev->flags)
-                   && !test_bit(Faulty, &rdev->flags)) {
+       while ((rdev = next_active_rdev(rdev, mddev)) != NULL) {
                        int size = PAGE_SIZE;
                        if (page->index == bitmap->file_pages-1)
                                size = roundup(bitmap->last_page_size,
@@ -281,8 +313,7 @@ static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
                                       + page->index * (PAGE_SIZE/512),
                                       size,
                                       page);
-               }
-       rcu_read_unlock();
+       }
 
        if (wait)
                md_super_wait(mddev);

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 8cfadc5bd2ba54f858c8f28c8f17c5db40942891..4790c83d78d0cd52adbfb4d4c394eb9d7ec4c691 100644 (file)
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -3841,8 +3841,6 @@ static int do_md_stop(mddev_t * mddev, int mode, int is_open)
 
                del_timer_sync(&mddev->safemode_timer);
 
-               invalidate_partition(disk, 0);
-
                switch(mode) {
                case 1: /* readonly */
                        err  = -ENXIO;