From: Jan Tulak <jtulak@redhat.com>
Date: Tue, 9 Oct 2018 16:49:47 +0000 (-0500)
Subject: mkfs: discard only after all validations
X-Git-Tag: v4.19.0-rc1~47
X-Git-Url: http://git.ipfire.org/?p=thirdparty%2Fxfsprogs-dev.git;a=commitdiff_plain;h=915a27a05b19017b478a9c2e356126373022847d

mkfs: discard only after all validations

Discard should happen only when everything has been validated, just
before we start writing to the device. If it happens earlier, it is
possible that mkfs will abort, but managed to already wipe data. This
patch moves the discard to the latest possible moment.

Signed-off-by: Jan Tulak <jtulak@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>
---

diff --git a/mkfs/xfs_mkfs.c b/mkfs/xfs_mkfs.c
index 7c05c6f6e..87ca1d274 100644
--- a/mkfs/xfs_mkfs.c
+++ b/mkfs/xfs_mkfs.c
@@ -2389,8 +2389,7 @@ _("log stripe unit (%d bytes) is too large (maximum is 256KiB)\n"
 static void
 open_devices(
 	struct mkfs_params	*cfg,
-	struct libxfs_xinit	*xi,
-	bool			discard)
+	struct libxfs_xinit	*xi)
 {
 	uint64_t		sector_mask;
 
@@ -2419,10 +2418,15 @@ open_devices(
 	xi->dsize &= sector_mask;
 	xi->rtsize &= sector_mask;
 	xi->logBBsize &= (uint64_t)-1 << (max(cfg->lsectorlog, 10) - BBSHIFT);
+}
 
-
-	if (!discard)
-		return;
+static void
+discard_devices(
+	struct libxfs_xinit	*xi)
+{
+	/*
+	 * This function has to be called after libxfs has been initialized.
+	 */
 
 	if (!xi->disfile)
 		discard_blocks(xi->ddev, xi->dsize);
@@ -3902,7 +3906,7 @@ main(
 	/*
 	 * Open and validate the device configurations
 	 */
-	open_devices(&cfg, &xi, (discard && !dry_run));
+	open_devices(&cfg, &xi);
 	validate_datadev(&cfg, &cli);
 	validate_logdev(&cfg, &cli, &logfile);
 	validate_rtdev(&cfg, &cli, &rtfile);
@@ -3953,6 +3957,12 @@ main(
 			exit(0);
 	}
 
+	/*
+	 * All values have been validated, discard the old device layout.
+	 */
+	if (discard && !dry_run)
+		discard_devices(&xi);
+
 	/*
 	 * we need the libxfs buffer cache from here on in.
 	 */