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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Jeff Layton <jlayton@kernel.org>,
        "Yan, Zheng" <zyan@redhat.com>, Ilya Dryomov <idryomov@gmail.com>
Subject: [PATCH 4.14 31/77] ceph: flush dirty inodes before proceeding with remount
Date:   Thu, 23 May 2019 21:05:49 +0200
Message-Id: <20190523181724.506434015@linuxfoundation.org>
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From: Jeff Layton <jlayton@kernel.org>

commit 00abf69dd24f4444d185982379c5cc3bb7b6d1fc upstream.

xfstest generic/452 was triggering a "Busy inodes after umount" warning.
ceph was allowing the mount to go read-only without first flushing out
dirty inodes in the cache. Ensure we sync out the filesystem before
allowing a remount to proceed.

Cc: stable@vger.kernel.org
Link: http://tracker.ceph.com/issues/39571
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/ceph/super.c |    7 +++++++
 1 file changed, 7 insertions(+)

--- a/fs/ceph/super.c
+++ b/fs/ceph/super.c
@@ -768,6 +768,12 @@ static void ceph_umount_begin(struct sup
 	return;
 }
 
+static int ceph_remount(struct super_block *sb, int *flags, char *data)
+{
+	sync_filesystem(sb);
+	return 0;
+}
+
 static const struct super_operations ceph_super_ops = {
 	.alloc_inode	= ceph_alloc_inode,
 	.destroy_inode	= ceph_destroy_inode,
@@ -775,6 +781,7 @@ static const struct super_operations cep
 	.drop_inode	= ceph_drop_inode,
 	.sync_fs        = ceph_sync_fs,
 	.put_super	= ceph_put_super,
+	.remount_fs	= ceph_remount,
 	.show_options   = ceph_show_options,
 	.statfs		= ceph_statfs,
 	.umount_begin   = ceph_umount_begin,