Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block

[linux-2.6-omap-h63xx.git] / drivers / md / bitmap.c

diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index 621a272a2c7495b9cd8866ec6bb6d0454d5d1396..ab7c8e4a61f943c516ae5a3534e8775c33180f6b 100644 (file)
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -208,15 +208,18 @@ static void bitmap_checkfree(struct bitmap *bitmap, unsigned long page)
  */
 
 /* IO operations when bitmap is stored near all superblocks */
-static struct page *read_sb_page(mddev_t *mddev, long offset, unsigned long index)
+static struct page *read_sb_page(mddev_t *mddev, long offset,
+                                struct page *page,
+                                unsigned long index, int size)
 {
        /* choose a good rdev and read the page from there */
 
        mdk_rdev_t *rdev;
        struct list_head *tmp;
-       struct page *page = alloc_page(GFP_KERNEL);
        sector_t target;
 
+       if (!page)
+               page = alloc_page(GFP_KERNEL);
        if (!page)
                return ERR_PTR(-ENOMEM);
 
@@ -227,7 +230,9 @@ static struct page *read_sb_page(mddev_t *mddev, long offset, unsigned long inde
 
                target = rdev->sb_start + offset + index * (PAGE_SIZE/512);
 
-               if (sync_page_io(rdev->bdev, target, PAGE_SIZE, page, READ)) {
+               if (sync_page_io(rdev->bdev, target,
+                                roundup(size, bdev_hardsect_size(rdev->bdev)),
+                                page, READ)) {
                        page->index = index;
                        attach_page_buffers(page, NULL); /* so that free_buffer will
                                                          * quietly no-op */
@@ -238,15 +243,47 @@ 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 +318,7 @@ 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);
@@ -513,7 +549,9 @@ static int bitmap_read_sb(struct bitmap *bitmap)
 
                bitmap->sb_page = read_page(bitmap->file, 0, bitmap, bytes);
        } else {
-               bitmap->sb_page = read_sb_page(bitmap->mddev, bitmap->offset, 0);
+               bitmap->sb_page = read_sb_page(bitmap->mddev, bitmap->offset,
+                                              NULL,
+                                              0, sizeof(bitmap_super_t));
        }
        if (IS_ERR(bitmap->sb_page)) {
                err = PTR_ERR(bitmap->sb_page);
@@ -926,11 +964,16 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
                                 */
                                page = bitmap->sb_page;
                                offset = sizeof(bitmap_super_t);
+                               read_sb_page(bitmap->mddev, bitmap->offset,
+                                            page,
+                                            index, count);
                        } else if (file) {
                                page = read_page(file, index, bitmap, count);
                                offset = 0;
                        } else {
-                               page = read_sb_page(bitmap->mddev, bitmap->offset, index);
+                               page = read_sb_page(bitmap->mddev, bitmap->offset,
+                                                   NULL,
+                                                   index, count);
                                offset = 0;
                        }
                        if (IS_ERR(page)) { /* read error */
@@ -1234,7 +1277,7 @@ 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;