FAILED: patch "[PATCH] ntfs: fail remount on sync errors and keep the dirty bit on SB_FORCE" failed to apply to 5.15-stable tree

[Sasha Levin <sashal@kernel.org>]

The patch below does not apply to the 5.15-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-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 17a1edda75fd371f36085b1568e0b70baff99969
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '20261107060858-failed-5.15-17a1edda75fd@kernel.org' --subject-prefix 'PATCH 5.15.y' 'HEAD^..'

Thanks,
Sasha

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

From 17a1edda75fd371f36085b1568e0b70baff99969 Mon Sep 17 00:00:00 2001
From: Hongling Zeng <zenghongling@kylinos.cn>
Date: Tue, 15 Sep 2026 16:32:52 +0800
Subject: [PATCH] ntfs: fail remount on sync errors and keep the dirty bit on
 SB_FORCE

ntfs_reconfigure() currently ignores sync_filesystem() errors, allowing
a regular read-only remount to succeed even when dirty data was not
synced. Check the error and fail regular remounts, leaving the
superblock read-write so ntfs_put_super() can retry at unmount.

SB_FORCE does not wait for writers already in progress, so it must not
clear the on-disk dirty bit. Warn and continue on sync errors for
SB_FORCE. A forced remount updates the dirty state only when errors
have been recorded, and never clears the dirty bit. Skip the commit if
that state update fails, since the in-memory flags may be inconsistent.

Reported-by: Hyunchul Lee <hyc.lee@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Hongling Zeng <zenghongling@kylinos.cn>
Reviewed-by: Hyunchul Lee <hyc.lee@gmail.com>
Reviewed-by: Baolin Liu <liubaolin@kylinos.cn>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
---
 fs/ntfs/super.c | 27 +++++++++++++++++++++------
 1 file changed, 21 insertions(+), 6 deletions(-)

diff --git a/fs/ntfs/super.c b/fs/ntfs/super.c
index 0ec4d2ddf6219..6a107ec0d0f68 100644
--- a/fs/ntfs/super.c
+++ b/fs/ntfs/super.c
@@ -273,7 +273,13 @@ static int ntfs_reconfigure(struct fs_context *fc)
 
 	ntfs_debug("Entering with remount");
 
-	sync_filesystem(sb);
+	err = sync_filesystem(sb);
+	if (err) {
+		ntfs_warning(sb, "Failed to sync the filesystem.");
+		/* A forced remount must still turn the superblock read-only. */
+		if (!(fc->sb_flags & SB_FORCE))
+			return err;
+	}
 
 	/*
 	 * For the read-write compiled driver, if we are remounting read-write,
@@ -336,11 +342,20 @@ static int ntfs_reconfigure(struct fs_context *fc)
 		 * or flush fails the remount, leaving the superblock
 		 * read-write so ntfs_put_super() retries at unmount.
 		 */
-		err = ntfs_sync_volume_dirty_state(vol);
-		if (err) {
-			ntfs_warning(sb,
-				"Failed to update dirty bit in volume information flags.  Run chkdsk.");
-			return err;
+		/*
+		 * A forced remount does not drain writers in progress,
+		 * so one may still be modifying metadata when the flags
+		 * are committed: never clear the dirty bit then; if
+		 * errors have been recorded, the update preserves or
+		 * sets it; otherwise, skip the update entirely.
+		 */
+		if (!(fc->sb_flags & SB_FORCE) || NVolErrors(vol)) {
+			err = ntfs_sync_volume_dirty_state(vol);
+			if (err) {
+				ntfs_warning(sb,
+					"Failed to update dirty bit in volume information flags.  Run chkdsk.");
+				return err;
+			}
 		}
 		if (NInoDirty(NTFS_I(vol->vol_ino))) {
 			/* ntfs_commit_inode() would discard the error. */
-- 
2.53.0