1 files changed, 21 insertions, 13 deletions

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 7031e9631519..61fb78f1ea5c 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1507,12 +1507,17 @@ static noinline ssize_t __btrfs_buffered_write(struct file *file,
 		}
 
 		reserve_bytes = num_pages << PAGE_CACHE_SHIFT;
-		ret = btrfs_check_data_free_space(inode, reserve_bytes, write_bytes);
-		if (ret == -ENOSPC &&
-		    (BTRFS_I(inode)->flags & (BTRFS_INODE_NODATACOW |
-					      BTRFS_INODE_PREALLOC))) {
+
+		if (BTRFS_I(inode)->flags & (BTRFS_INODE_NODATACOW |
+					     BTRFS_INODE_PREALLOC)) {
 			ret = check_can_nocow(inode, pos, &write_bytes);
+			if (ret < 0)
+				break;
 			if (ret > 0) {
+				/*
+				 * For nodata cow case, no need to reserve
+				 * data space.
+				 */
 				only_release_metadata = true;
 				/*
 				 * our prealloc extent may be smaller than
@@ -1521,20 +1526,19 @@ static noinline ssize_t __btrfs_buffered_write(struct file *file,
 				num_pages = DIV_ROUND_UP(write_bytes + offset,
 							 PAGE_CACHE_SIZE);
 				reserve_bytes = num_pages << PAGE_CACHE_SHIFT;
-				ret = 0;
-			} else {
-				ret = -ENOSPC;
+				goto reserve_metadata;
 			}
 		}
-
-		if (ret)
+		ret = __btrfs_check_data_free_space(inode, pos, write_bytes);
+		if (ret < 0)
 			break;
 
+reserve_metadata:
 		ret = btrfs_delalloc_reserve_metadata(inode, reserve_bytes);
 		if (ret) {
 			if (!only_release_metadata)
-				btrfs_free_reserved_data_space(inode,
-							       reserve_bytes);
+				__btrfs_free_reserved_data_space(inode, pos,
+							         write_bytes);
 			else
 				btrfs_end_write_no_snapshoting(root);
 			break;
@@ -2566,8 +2570,11 @@ static long btrfs_fallocate(struct file *file, int mode,
 	/*
 	 * Make sure we have enough space before we do the
 	 * allocation.
+	 * XXX: The behavior must be changed to do accurate check first
+	 * and then check data reserved space.
 	 */
-	ret = btrfs_check_data_free_space(inode, alloc_end - alloc_start, alloc_end - alloc_start);
+	ret = btrfs_check_data_free_space(inode, alloc_start,
+					  alloc_end - alloc_start);
 	if (ret)
 		return ret;
 
@@ -2700,7 +2707,8 @@ static long btrfs_fallocate(struct file *file, int mode,
 out:
 	mutex_unlock(&inode->i_mutex);
 	/* Let go of our reservation. */
-	btrfs_free_reserved_data_space(inode, alloc_end - alloc_start);
+	__btrfs_free_reserved_data_space(inode, alloc_start,
+					 alloc_end - alloc_start);
 	return ret;
 }