[V2] mkfs: default to CRC enabled filesystems

[Dave Chinner]

From: Dave Chinner <dchinner at redhat.com>

It's time to change the mkfs defaults to enable CRCs for all new
filesystems. While there, also enable the free inode btree by
default, too, as that functionality has also had long enough to make
it into distro kernels, too. Also update the man page to reflect the
change in defaults.

Signed-off-by: Dave Chinner <dchinner at redhat.com>
---
 man/man8/mkfs.xfs.8 |  9 +++++----
 mkfs/xfs_mkfs.c     | 27 +++++++++++++++++----------
 2 files changed, 22 insertions(+), 14 deletions(-)

diff --git a/man/man8/mkfs.xfs.8 b/man/man8/mkfs.xfs.8
index ad9ff3d..e18f6d1 100644
--- a/man/man8/mkfs.xfs.8
+++ b/man/man8/mkfs.xfs.8
@@ -150,7 +150,7 @@ of calculating and checking the CRCs is not noticable in normal operation.
 .IP
 By default,
 .B mkfs.xfs
-will not enable metadata CRCs.
+will enable metadata CRCs.
 .TP
 .BI finobt= value
 This option enables the use of a separate free inode btree index in each
@@ -164,10 +164,11 @@ filesystems age.
 .IP
 By default,
 .B mkfs.xfs
-will not create free inode btrees. This feature is also currently only available
-for filesystems created with the
+will create free inode btrees for filesystems created with the (default)
 .B \-m crc=1
-option set.
+option set. When the option
+.B \-m crc=0
+is used, the free inode btree feature is not supported and is disabled.
 .RE
 .TP
 .BI \-d " data_section_options"
diff --git a/mkfs/xfs_mkfs.c b/mkfs/xfs_mkfs.c
index 5084d75..0218491 100644
--- a/mkfs/xfs_mkfs.c
+++ b/mkfs/xfs_mkfs.c
@@ -1004,6 +1004,7 @@ main(
 	int			lazy_sb_counters;
 	int			crcs_enabled;
 	int			finobt;
+	bool			finobtflag;
 
 	progname = basename(argv[0]);
 	setlocale(LC_ALL, "");
@@ -1036,8 +1037,9 @@ main(
 	force_overwrite = 0;
 	worst_freelist = 0;
 	lazy_sb_counters = 1;
-	crcs_enabled = 0;
-	finobt = 0;
+	crcs_enabled = 1;
+	finobt = 1;
+	finobtflag = false;
 	memset(&fsx, 0, sizeof(fsx));
 
 	memset(&xi, 0, sizeof(xi));
@@ -1538,6 +1540,7 @@ _("cannot specify both crc and ftype\n"));
 					if (c < 0 || c > 1)
 						illegal(value, "m finobt");
 					finobt = c;
+					finobtflag = true;
 					break;
 				default:
 					unknown('m', value);
@@ -1878,15 +1881,19 @@ _("V2 attribute format always enabled on CRC enabled filesytems\n"));
 _("32 bit Project IDs always enabled on CRC enabled filesytems\n"));
 			usage();
 		}
-	}
-
-	/*
-	 * The kernel doesn't currently support crc=0,finobt=1 filesystems.
-	 * Catch it here, disable finobt and warn the user.
-	 */
-	if (finobt && !crcs_enabled) {
-		fprintf(stderr,
+	} else {
+		/*
+		 * The kernel doesn't currently support crc=0,finobt=1
+		 * filesystems. If crcs are not enabled and the user has
+		 * explicitly turned them off then silently turn them off
+		 * to avoid an unnecessary warning. If the user explicitly
+		 * tried to use crc=0,finobt=1, then issue a warning before
+		 * turning them off.
+		 */
+		if (finobt && finobtflag) {
+			fprintf(stderr,
 _("warning: finobt not supported without CRC support, disabled.\n"));
+		}
 		finobt = 0;
 	}
 
-- 
2.0.0