3 files changed, 17 insertions, 15 deletions

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 2a3624adc0cf..17c508a941eb 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -1988,9 +1988,12 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
         u64 nr_delalloc;
         u64 delalloc_end;
 
+
         WARN_ON(!PageLocked(page));
-        if (page->index > end_index) {
-                clear_extent_dirty(tree, start, page_end, GFP_NOFS);
+        page_offset = i_size & (PAGE_CACHE_SIZE - 1);
+        if (page->index > end_index ||
+           (page->index == end_index && !page_offset)) {
+                page->mapping->a_ops->invalidatepage(page, 0);
                 unlock_page(page);
                 return 0;
         }
@@ -1998,13 +2001,13 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
         if (page->index == end_index) {
                 char *userpage;
 
-                size_t offset = i_size & (PAGE_CACHE_SIZE - 1);
-
                 userpage = kmap_atomic(page, KM_USER0);
-                memset(userpage + offset, 0, PAGE_CACHE_SIZE - offset);
-                flush_dcache_page(page);
+                memset(userpage + page_offset, 0,
+                       PAGE_CACHE_SIZE - page_offset);
                 kunmap_atomic(userpage, KM_USER0);
+                flush_dcache_page(page);
         }
+        page_offset = 0;
 
         set_page_extent_mapped(page);
 
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index df97d470812a..d968900c6973 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -305,7 +305,6 @@ static int noinline dirty_and_release_pages(struct btrfs_trans_handle *trans,
             (inline_size & (root->sectorsize -1)) == 0 ||
             inline_size >= BTRFS_MAX_INLINE_DATA_SIZE(root)) {
                 u64 last_end;
-                u64 existing_delalloc = 0;
 
                 for (i = 0; i < num_pages; i++) {
                         struct page *p = pages[i];
@@ -315,13 +314,6 @@ static int noinline dirty_and_release_pages(struct btrfs_trans_handle *trans,
                 last_end = (u64)(pages[num_pages -1]->index) <<
                                 PAGE_CACHE_SHIFT;
                 last_end += PAGE_CACHE_SIZE - 1;
-                if (start_pos < isize) {
-                        u64 delalloc_start = start_pos;
-                        existing_delalloc = count_range_bits(io_tree,
-                                             &delalloc_start,
-                                             end_of_last_block, (u64)-1,
-                                             EXTENT_DELALLOC);
-                }
                 set_extent_delalloc(io_tree, start_pos, end_of_last_block,
                                  GFP_NOFS);
                 btrfs_add_ordered_inode(inode);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 08760ff9bab7..40b4a8ec17fe 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -1180,19 +1180,26 @@ static int btrfs_truncate_page(struct address_space *mapping, loff_t from)
                 goto out;
 
         ret = -ENOMEM;
+again:
         page = grab_cache_page(mapping, index);
         if (!page)
                 goto out;
         if (!PageUptodate(page)) {
                 ret = btrfs_readpage(NULL, page);
                 lock_page(page);
+                if (page->mapping != mapping) {
+                        unlock_page(page);
+                        page_cache_release(page);
+                        goto again;
+                }
                 if (!PageUptodate(page)) {
                         ret = -EIO;
                         goto out;
                 }
         }
-        page_start = (u64)page->index << PAGE_CACHE_SHIFT;
 
+        page_start = (u64)page->index << PAGE_CACHE_SHIFT;
+        wait_on_page_writeback(page);
         ret = btrfs_cow_one_page(inode, page, offset);
 
         unlock_page(page);