From: Alexey Nepomnyashih <sdl@nppct.ru>
Date: Wed, 3 Jun 2026 20:41:47 +0000 (+0000)
Subject: xfs: fix unreachable BIGTIME check in dquot flush validation
X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=03866d130ed33ab68cc7faaf4bf2c4abef96d42e;p=thirdparty%2Flinux.git

xfs: fix unreachable BIGTIME check in dquot flush validation

The dqp->q_id == 0 check inside the XFS_DQTYPE_BIGTIME block is
unreachable because root dquots return successfully earlier. Reject root
dquots with XFS_DQTYPE_BIGTIME before that early return, preserving the
intended validation and removing the unreachable condition.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 4ea1ff3b4968 ("xfs: widen ondisk quota expiration timestamps to handle y2038+")
Cc: stable@vger.kernel.org # v5.10+
Signed-off-by: Alexey Nepomnyashih <sdl@nppct.ru>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Reviewed-by: Allison Henderson <achender@kernel.org>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
---

diff --git a/fs/xfs/xfs_dquot.c b/fs/xfs/xfs_dquot.c
index 69e9bc588c8b6..c311f61d95541 100644
--- a/fs/xfs/xfs_dquot.c
+++ b/fs/xfs/xfs_dquot.c
@@ -1216,6 +1216,14 @@ xfs_qm_dqflush_check(
 	    type != XFS_DQTYPE_PROJ)
 		return __this_address;
 
+	/* bigtime flag should never be set on root dquots */
+	if (dqp->q_type & XFS_DQTYPE_BIGTIME) {
+		if (!xfs_has_bigtime(dqp->q_mount))
+			return __this_address;
+		if (dqp->q_id == 0)
+			return __this_address;
+	}
+
 	if (dqp->q_id == 0)
 		return NULL;
 
@@ -1231,14 +1239,6 @@ xfs_qm_dqflush_check(
 	    !dqp->q_rtb.timer)
 		return __this_address;
 
-	/* bigtime flag should never be set on root dquots */
-	if (dqp->q_type & XFS_DQTYPE_BIGTIME) {
-		if (!xfs_has_bigtime(dqp->q_mount))
-			return __this_address;
-		if (dqp->q_id == 0)
-			return __this_address;
-	}
-
 	return NULL;
 }