[PATCH 21/37] tune2fs: Enable extent tree checksums

["Darrick J. Wong" <djwong@us.ibm.com>]

Add to tune2fs the ability to recalculate extent tree checksums when altering
the metadata checksum feature flag.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
---
 misc/tune2fs.c |   50 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 50 insertions(+), 0 deletions(-)


diff --git a/misc/tune2fs.c b/misc/tune2fs.c
index dd4011e..0c0a911 100644
--- a/misc/tune2fs.c
+++ b/misc/tune2fs.c
@@ -355,6 +355,49 @@ static void request_fsck_afterwards(ext2_filsys fs)
 		printf(_("(and reboot afterwards!)\n"));
 }
 
+/* Rewrite extents */
+static errcode_t rewrite_extents(ext2_filsys fs, ext2_ino_t ino,
+				 struct ext2_inode_large *inode)
+{
+	ext2_extent_handle_t	handle;
+	struct ext2fs_extent	extent;
+	int			op = EXT2_EXTENT_ROOT;
+	unsigned int		printed = 0;
+	errcode_t		errcode;
+
+	if (!(inode->i_flags & EXT4_EXTENTS_FL))
+		return 0;
+
+	errcode = ext2fs_extent_open(fs, ino, &handle);
+	if (errcode)
+		return errcode;
+
+	while (1) {
+		errcode = ext2fs_extent_get(handle, op, &extent);
+		if (errcode)
+			break;
+
+		/* Root node is in the separately checksummed inode */
+		if (op == EXT2_EXTENT_ROOT) {
+			op = EXT2_EXTENT_NEXT;
+			continue;
+		}
+		op = EXT2_EXTENT_NEXT;
+
+		/* Only visit the first extent in each extent block */
+		if (extent.e_flags & EXT2_EXTENT_FLAGS_SECOND_VISIT)
+			continue;
+		errcode = ext2fs_extent_replace(handle, 0, &extent);
+		if (errcode)
+			break;
+	}
+
+	/* Ok if we run off the end */
+	if (errcode == EXT2_ET_EXTENT_NO_NEXT)
+		errcode = 0;
+	return errcode;
+}
+
 /*
  * Forcibly set checksums in all inodes.
  */
@@ -387,6 +430,13 @@ static void rewrite_inodes(ext2_filsys fs)
 			com_err("set_csum", retval, "while writing inode");
 			exit(1);
 		}
+
+		retval = rewrite_extents(fs, ino, &inode);
+		if (retval) {
+			com_err("rewrite_extents", retval,
+				"while rewriting extents");
+			exit(1);
+		}
 	} while (ino);
 	ext2fs_close_inode_scan(scan);
 }