[PATCH] md: fix bitmap/read_sb_page so that it handles errors properly.

read_sb_page() assumed that if sync_page_io fails, the device would be marked
faultly.  However it isn't.  So in the face of error, read_sb_page would loop
forever.

Redo the logic so that this cannot happen.

Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 10 insertions, 9 deletions

diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index c971d38f3a05..90fe70d76a31 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -270,19 +270,20 @@ static struct page *read_sb_page(mddev_t *mddev, long offset, unsigned long inde
 
         if (!page)
                 return ERR_PTR(-ENOMEM);
-        do {
-                ITERATE_RDEV(mddev, rdev, tmp)
-                        if (rdev->in_sync && !rdev->faulty)
-                                goto found;
-                return ERR_PTR(-EIO);
 
-        found:
+        ITERATE_RDEV(mddev, rdev, tmp) {
+                if (! rdev->in_sync || rdev->faulty)
+                        continue;
+
                 target = (rdev->sb_offset << 1) + offset + index * (PAGE_SIZE/512);
 
-        } while (!sync_page_io(rdev->bdev, target, PAGE_SIZE, page, READ));
+                if (sync_page_io(rdev->bdev, target, PAGE_SIZE, page, READ)) {
+                        page->index = index;
+                        return page;
+                }
+        }
+        return ERR_PTR(-EIO);
 
-        page->index = index;
-        return page;
 }
 
 static int write_sb_page(mddev_t *mddev, long offset, struct page *page, int wait)