fs: Add support FALLOC_FL_INSERT_RANGE for fallocate

FALLOC_FL_INSERT_RANGE command is the opposite command of
FALLOC_FL_COLLAPSE_RANGE that is needed for someone who wants to add
some data in the middle of file.

FALLOC_FL_INSERT_RANGE will create space for writing new data within
a file after shifting extents to right as given length. This command
also has same limitations as FALLOC_FL_COLLAPSE_RANGE in that
operations need to be filesystem block boundary aligned and cannot
cross the current EOF.

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Ashish Sangwan <a.sangwan@samsung.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>


diff --git a/include/linux/falloc.h b/include/linux/falloc.h
index 3159168..9961110 100644
--- a/include/linux/falloc.h
+++ b/include/linux/falloc.h
@@ -21,4 +21,10 @@
 #define FS_IOC_RESVSP		_IOW('X', 40, struct space_resv)
 #define FS_IOC_RESVSP64		_IOW('X', 42, struct space_resv)
 
+#define	FALLOC_FL_SUPPORTED_MASK	(FALLOC_FL_KEEP_SIZE |		\
+					 FALLOC_FL_PUNCH_HOLE |		\
+					 FALLOC_FL_COLLAPSE_RANGE |	\
+					 FALLOC_FL_ZERO_RANGE |		\
+					 FALLOC_FL_INSERT_RANGE)
+
 #endif /* _FALLOC_H_ */