FAILED: patch "[PATCH] xfs: fix unreachable BIGTIME check in dquot flush validation" failed to apply to 5.10-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y
git checkout FETCH_HEAD
git cherry-pick -x 03866d130ed33ab68cc7faaf4bf2c4abef96d42e
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026071407-parmesan-cyclic-e3d5@gregkh' --subject-prefix 'PATCH 5.10.y' 'HEAD^..'

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 03866d130ed33ab68cc7faaf4bf2c4abef96d42e Mon Sep 17 00:00:00 2001
From: Alexey Nepomnyashih <sdl@nppct.ru>
Date: Wed, 3 Jun 2026 20:41:47 +0000
Subject: [PATCH] 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 69e9bc588c8b..c311f61d9554 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;
 }