1 files changed, 20 insertions, 4 deletions

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 54d013c3bb88..a0f3804efe4f 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2398,7 +2398,8 @@ update_nr_written:
 int extent_write_cache_pages(struct extent_io_tree *tree,
                              struct address_space *mapping,
                              struct writeback_control *wbc,
-                             writepage_t writepage, void *data)
+                             writepage_t writepage, void *data,
+                             void (*flush_fn)(void *))
 {
         struct backing_dev_info *bdi = mapping->backing_dev_info;
         int ret = 0;
@@ -2460,8 +2461,10 @@ retry:
                                 continue;
                         }
 
-                        if (wbc->sync_mode != WB_SYNC_NONE)
+                        if (wbc->sync_mode != WB_SYNC_NONE) {
+                                flush_fn(data);
                                 wait_on_page_writeback(page);
+                        }
 
                         if (PageWriteback(page) ||
                             !clear_page_dirty_for_io(page)) {
@@ -2498,6 +2501,15 @@ retry:
 }
 EXPORT_SYMBOL(extent_write_cache_pages);
 
+static noinline void flush_write_bio(void *data)
+{
+        struct extent_page_data *epd = data;
+        if (epd->bio) {
+                submit_one_bio(WRITE, epd->bio, 0, 0);
+                epd->bio = NULL;
+        }
+}
+
 int extent_write_full_page(struct extent_io_tree *tree, struct page *page,
                           get_extent_t *get_extent,
                           struct writeback_control *wbc)
@@ -2523,7 +2535,7 @@ int extent_write_full_page(struct extent_io_tree *tree, struct page *page,
         ret = __extent_writepage(page, wbc, &epd);
 
         extent_write_cache_pages(tree, mapping, &wbc_writepages,
-                                 __extent_writepage, &epd);
+                                 __extent_writepage, &epd, flush_write_bio);
         if (epd.bio) {
                 submit_one_bio(WRITE, epd.bio, 0, 0);
         }
@@ -2592,7 +2604,8 @@ int extent_writepages(struct extent_io_tree *tree,
         };
 
         ret = extent_write_cache_pages(tree, mapping, wbc,
-                                       __extent_writepage, &epd);
+                                       __extent_writepage, &epd,
+                                       flush_write_bio);
         if (epd.bio) {
                 submit_one_bio(WRITE, epd.bio, 0, 0);
         }
@@ -3087,6 +3100,9 @@ int clear_extent_buffer_dirty(struct extent_io_tree *tree,
 
         for (i = 0; i < num_pages; i++) {
                 page = extent_buffer_page(eb, i);
+                if (!set && !PageDirty(page))
+                        continue;
+
                 lock_page(page);
                 if (i == 0)
                         set_page_extent_head(page, eb->len);