diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 1933e8b07ed7..159a93450e26 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1596,6 +1596,13 @@ static noinline ssize_t __btrfs_buffered_write(struct file *file,
 
 		copied = btrfs_copy_from_user(pos, write_bytes, pages, i);
 
+		num_sectors = BTRFS_BYTES_TO_BLKS(root->fs_info,
+						reserve_bytes);
+		dirty_sectors = round_up(copied + sector_offset,
+					root->sectorsize);
+		dirty_sectors = BTRFS_BYTES_TO_BLKS(root->fs_info,
+						dirty_sectors);
+
 		/*
 		 * if we have trouble faulting in the pages, fall
 		 * back to one page at a time
@@ -1605,6 +1612,7 @@ static noinline ssize_t __btrfs_buffered_write(struct file *file,
 
 		if (copied == 0) {
 			force_page_uptodate = true;
+			dirty_sectors = 0;
 			dirty_pages = 0;
 		} else {
 			force_page_uptodate = false;
@@ -1615,20 +1623,19 @@ static noinline ssize_t __btrfs_buffered_write(struct file *file,
 		/*
 		 * If we had a short copy we need to release the excess delaloc
 		 * bytes we reserved.  We need to increment outstanding_extents
-		 * because btrfs_delalloc_release_space will decrement it, but
+		 * because btrfs_delalloc_release_space and
+		 * btrfs_delalloc_release_metadata will decrement it, but
 		 * we still have an outstanding extent for the chunk we actually
 		 * managed to copy.
 		 */
-		num_sectors = BTRFS_BYTES_TO_BLKS(root->fs_info,
-						reserve_bytes);
-		dirty_sectors = round_up(copied + sector_offset,
-					root->sectorsize);
-		dirty_sectors = BTRFS_BYTES_TO_BLKS(root->fs_info,
-						dirty_sectors);
-
 		if (num_sectors > dirty_sectors) {
-			release_bytes = (write_bytes - copied)
-				& ~((u64)root->sectorsize - 1);
+			/*
+			 * we round down because we don't want to count
+			 * any partial blocks actually sent through the
+			 * IO machines
+			 */
+			release_bytes = round_down(release_bytes - copied,
+				      root->sectorsize);
 			if (copied > 0) {
 				spin_lock(&BTRFS_I(inode)->lock);
 				BTRFS_I(inode)->outstanding_extents++;