[PATCH] md: don't skip bitmap pages due to lack of bit that we just cleared.

When looking for pages that need cleaning we skip pages that don't have
BITMAP_PAGE_CLEAN set.  But if it is the 'current' page we will have cleared
that bit ourselves, so skipping it is wrong.  So: move the 'skip this page'
inside 'if page != lastpage'.

Also fold call of file_page_offset into the one place where the value (bit) is
used.

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, 17 insertions, 18 deletions

diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index 86b6b037fa44..204564dc6a0d 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -897,7 +897,7 @@ static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
 
 int bitmap_daemon_work(struct bitmap *bitmap)
 {
-        unsigned long bit, j;
+        unsigned long j;
         unsigned long flags;
         struct page *page = NULL, *lastpage = NULL;
         int err = 0;
@@ -920,24 +920,23 @@ int bitmap_daemon_work(struct bitmap *bitmap)
                 }
 
                 page = filemap_get_page(bitmap, j);
-                /* skip this page unless it's marked as needing cleaning */
-                if (!((attr=get_page_attr(bitmap, page)) & BITMAP_PAGE_CLEAN)) {
-                        if (attr & BITMAP_PAGE_NEEDWRITE) {
-                                page_cache_get(page);
-                                clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
-                        }
-                        spin_unlock_irqrestore(&bitmap->lock, flags);
-                        if (attr & BITMAP_PAGE_NEEDWRITE) {
-                                if (write_page(bitmap, page, 0))
-                                        bitmap_file_kick(bitmap);
-                                page_cache_release(page);
-                        }
-                        continue;
-                }
-
-                bit = file_page_offset(j);
 
                 if (page != lastpage) {
+                        /* skip this page unless it's marked as needing cleaning */
+                        if (!((attr=get_page_attr(bitmap, page)) & BITMAP_PAGE_CLEAN)) {
+                                if (attr & BITMAP_PAGE_NEEDWRITE) {
+                                        page_cache_get(page);
+                                        clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
+                                }
+                                spin_unlock_irqrestore(&bitmap->lock, flags);
+                                if (attr & BITMAP_PAGE_NEEDWRITE) {
+                                        if (write_page(bitmap, page, 0))
+                                                bitmap_file_kick(bitmap);
+                                        page_cache_release(page);
+                                }
+                                continue;
+                        }
+
                         /* grab the new page, sync and release the old */
                         page_cache_get(page);
                         if (lastpage != NULL) {
@@ -979,7 +978,7 @@ int bitmap_daemon_work(struct bitmap *bitmap)
                                                   -1);
 
                                 /* clear the bit */
-                                clear_bit(bit, page_address(page));
+                                clear_bit(file_page_offset(j), page_address(page));
                         }
                 }
                 spin_unlock_irqrestore(&bitmap->lock, flags);