xfs: Check for extent overflow when swapping extents

Source kernel commit: bcc561f21f115437a010307420fc43d91be91c66

Removing an initial range of source/donor file's extent and adding a new
extent (from donor/source file) in its place will cause extent count to
increase by 1.

Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>

diff --git a/libxfs/xfs_inode_fork.h b/libxfs/xfs_inode_fork.h
index c8f279edc5c1ff307d982f8e60d881fdb08b41a5..9e2137cd73724b965c4dca278ec3114d8a13b632 100644 (file)
--- a/libxfs/xfs_inode_fork.h
+++ b/libxfs/xfs_inode_fork.h
@@ -88,6 +88,13 @@ struct xfs_ifork {
  */
 #define XFS_IEXT_REFLINK_END_COW_CNT   (2)
 
+/*
+ * Removing an initial range of source/donor file's extent and adding a new
+ * extent (from donor/source file) in its place will cause extent count to
+ * increase by 1.
+ */
+#define XFS_IEXT_SWAP_RMAP_CNT         (1)
+
 /*
  * Fork handling.
  */