1 files changed, 15 insertions, 12 deletions

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 3153b4fdd0b3..d4a63ae7ed1b 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2000,7 +2000,7 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
         struct block_device *bdev;
         int ret;
         int nr = 0;
-        size_t page_offset = 0;
+        size_t pg_offset = 0;
         size_t blocksize;
         loff_t i_size = i_size_read(inode);
         unsigned long end_index = i_size >> PAGE_CACHE_SHIFT;
@@ -2008,9 +2008,9 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
         u64 delalloc_end;
 
         WARN_ON(!PageLocked(page));
-        page_offset = i_size & (PAGE_CACHE_SIZE - 1);
+        pg_offset = i_size & (PAGE_CACHE_SIZE - 1);
         if (page->index > end_index ||
-           (page->index == end_index && !page_offset)) {
+           (page->index == end_index && !pg_offset)) {
                 page->mapping->a_ops->invalidatepage(page, 0);
                 unlock_page(page);
                 return 0;
@@ -2020,12 +2020,12 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
                 char *userpage;
 
                 userpage = kmap_atomic(page, KM_USER0);
-                memset(userpage + page_offset, 0,
-                       PAGE_CACHE_SIZE - page_offset);
+                memset(userpage + pg_offset, 0,
+                       PAGE_CACHE_SIZE - pg_offset);
                 kunmap_atomic(userpage, KM_USER0);
                 flush_dcache_page(page);
         }
-        page_offset = 0;
+        pg_offset = 0;
 
         set_page_extent_mapped(page);
 
@@ -2088,7 +2088,7 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
                         unlock_start = page_end + 1;
                         break;
                 }
-                em = epd->get_extent(inode, page, page_offset, cur,
+                em = epd->get_extent(inode, page, pg_offset, cur,
                                      end - cur + 1, 1);
                 if (IS_ERR(em) || !em) {
                         SetPageError(page);
@@ -2113,12 +2113,13 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
 
                         unlock_extent(tree, unlock_start, cur + iosize -1,
                                       GFP_NOFS);
+
                         if (tree->ops && tree->ops->writepage_end_io_hook)
                                 tree->ops->writepage_end_io_hook(page, cur,
                                                          cur + iosize - 1,
                                                          NULL, 1);
                         cur = cur + iosize;
-                        page_offset += iosize;
+                        pg_offset += iosize;
                         unlock_start = cur;
                         continue;
                 }
@@ -2127,7 +2128,7 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
                 if (0 && !test_range_bit(tree, cur, cur + iosize - 1,
                                    EXTENT_DIRTY, 0)) {
                         cur = cur + iosize;
-                        page_offset += iosize;
+                        pg_offset += iosize;
                         continue;
                 }
                 clear_extent_dirty(tree, cur, cur + iosize - 1, GFP_NOFS);
@@ -2141,6 +2142,7 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
                         SetPageError(page);
                 } else {
                         unsigned long max_nr = end_index + 1;
+
                         set_range_writeback(tree, cur, cur + iosize - 1);
                         if (!PageWriteback(page)) {
                                 printk("warning page %lu not writeback, "
@@ -2150,14 +2152,14 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
                         }
 
                         ret = submit_extent_page(WRITE, tree, page, sector,
-                                                 iosize, page_offset, bdev,
+                                                 iosize, pg_offset, bdev,
                                                  &epd->bio, max_nr,
                                                  end_bio_extent_writepage, 0);
                         if (ret)
                                 SetPageError(page);
                 }
                 cur = cur + iosize;
-                page_offset += iosize;
+                pg_offset += iosize;
                 nr++;
         }
 done:
@@ -2579,7 +2581,8 @@ int try_release_extent_mapping(struct extent_map_tree *map,
                                 spin_unlock(&map->lock);
                                 break;
                         }
-                        if (em->start != start) {
+                        if (test_bit(EXTENT_FLAG_PINNED, &em->flags) ||
+                            em->start != start) {
                                 spin_unlock(&map->lock);
                                 free_extent_map(em);
                                 break;