[PATCH v17 13/21] xfs: add XFS_BMAPI_UNWRITTEN to unmap unwritten extents in __xfs_bunmapi()

[Andrey Albershteyn <aalbersh@kernel.org>]

The __xfs_bunmapi() is used to remove all extents past EOF. Add
XFS_BMAPI_UNWRITTEN to remove only unwritten extents, while leaving
written ones in place. This will be used in following patch to clean up
unwritten extents on fsverity inodes.

Signed-off-by: Andrey Albershteyn <aalbersh@kernel.org>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
---
 fs/xfs/libxfs/xfs_bmap.c | 6 +++++-
 fs/xfs/libxfs/xfs_bmap.h | 6 +++++-
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index 9dc96a4edea6..6f0094445cea 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -5278,6 +5278,10 @@ __xfs_bunmapi(
 		if (del.br_startoff + del.br_blockcount > end + 1)
 			del.br_blockcount = end + 1 - del.br_startoff;
 
+		if ((flags & XFS_BMAPI_UNWRITTEN) &&
+		    del.br_state != XFS_EXT_UNWRITTEN)
+			goto skip;
+
 		if (!isrt || (flags & XFS_BMAPI_REMAP))
 			goto delete;
 
@@ -5412,7 +5416,7 @@ __xfs_bunmapi(
 			if (error)
 				goto error0;
 		}
-
+skip:
 		end = del.br_startoff - 1;
 nodelete:
 		/*
diff --git a/fs/xfs/libxfs/xfs_bmap.h b/fs/xfs/libxfs/xfs_bmap.h
index d5f2729305fa..0f36431d9936 100644
--- a/fs/xfs/libxfs/xfs_bmap.h
+++ b/fs/xfs/libxfs/xfs_bmap.h
@@ -90,6 +90,9 @@ struct xfs_bmalloca {
 /* Try to align allocations to the extent size hint */
 #define XFS_BMAPI_EXTSZALIGN	(1u << 11)
 
+/* Process unwritten extents only. Used for unmapping */
+#define XFS_BMAPI_UNWRITTEN	(1u << 12)
+
 #define XFS_BMAPI_FLAGS \
 	{ XFS_BMAPI_ENTIRE,	"ENTIRE" }, \
 	{ XFS_BMAPI_METADATA,	"METADATA" }, \
@@ -102,7 +105,8 @@ struct xfs_bmalloca {
 	{ XFS_BMAPI_COWFORK,	"COWFORK" }, \
 	{ XFS_BMAPI_NODISCARD,	"NODISCARD" }, \
 	{ XFS_BMAPI_NORMAP,	"NORMAP" },\
-	{ XFS_BMAPI_EXTSZALIGN,	"EXTSZALIGN" }
+	{ XFS_BMAPI_EXTSZALIGN,	"EXTSZALIGN" }, \
+	{ XFS_BMAPI_UNWRITTEN,	"UNWRITTEN" }
 
 
 static inline int xfs_bmapi_aflag(int w)
-- 
2.54.0