Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6

[linux-2.6] / drivers / md / bitmap.c

diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index dedba16d42f723cb75f87396659e31899d010fc8..ac89a5deaca2e12fa62ccb78f1d62b088039675c 100644 (file)
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -225,7 +225,7 @@ static struct page *read_sb_page(mddev_t *mddev, long offset, unsigned long inde
                    || test_bit(Faulty, &rdev->flags))
                        continue;
 
-               target = (rdev->sb_offset << 1) + offset + index * (PAGE_SIZE/512);
+               target = rdev->sb_start + offset + index * (PAGE_SIZE/512);
 
                if (sync_page_io(rdev->bdev, target, PAGE_SIZE, page, READ)) {
                        page->index = index;
@@ -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;
-       struct list_head *tmp;
+       mdk_rdev_t *rdev = NULL;
        mddev_t *mddev = bitmap->mddev;
 
-       rdev_for_each(rdev, tmp, 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,
@@ -260,32 +292,36 @@ static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
                                    + (long)(page->index * (PAGE_SIZE/512))
                                    + size/512 > 0)
                                        /* bitmap runs in to metadata */
-                                       return -EINVAL;
+                                       goto bad_alignment;
                                if (rdev->data_offset + mddev->size*2
-                                   > rdev->sb_offset*2 + bitmap->offset)
+                                   > rdev->sb_start + bitmap->offset)
                                        /* data runs in to bitmap */
-                                       return -EINVAL;
-                       } else if (rdev->sb_offset*2 < rdev->data_offset) {
+                                       goto bad_alignment;
+                       } else if (rdev->sb_start < rdev->data_offset) {
                                /* METADATA BITMAP DATA */
-                               if (rdev->sb_offset*2
+                               if (rdev->sb_start
                                    + bitmap->offset
                                    + page->index*(PAGE_SIZE/512) + size/512
                                    > rdev->data_offset)
                                        /* bitmap runs in to data */
-                                       return -EINVAL;
+                                       goto bad_alignment;
                        } else {
                                /* DATA METADATA BITMAP - no problems */
                        }
                        md_super_write(mddev, rdev,
-                                      (rdev->sb_offset<<1) + bitmap->offset
+                                      rdev->sb_start + bitmap->offset
                                       + page->index * (PAGE_SIZE/512),
                                       size,
                                       page);
-               }
+       }
 
        if (wait)
                md_super_wait(mddev);
        return 0;
+
+ bad_alignment:
+       rcu_read_unlock();
+       return -EINVAL;
 }
 
 static void bitmap_file_kick(struct bitmap *bitmap);
@@ -1229,7 +1265,7 @@ int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sect
                case 0:
                        bitmap_file_set_bit(bitmap, offset);
                        bitmap_count_page(bitmap,offset, 1);
-                       blk_plug_device(bitmap->mddev->queue);
+                       blk_plug_device_unlocked(bitmap->mddev->queue);
                        /* fall through */
                case 1:
                        *bmc = 2;