From a6097180d884ddab769fb25588ea8598589c218c Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.de>
Date: Mon, 17 Jan 2022 09:07:26 +1100
Subject: devtmpfs regression fix: reconfigure on each mount
Prior to Linux v5.4 devtmpfs used mount_single() which treats the given
mount options as "remount" options, so it updates the configuration of
the single super_block on each mount.
Since that was changed, the mount options used for devtmpfs are ignored.
This is a regression which affect systemd - which mounts devtmpfs with
"-o mode=755,size=4m,nr_inodes=1m".
This patch restores the "remount" effect by calling reconfigure_single()
Fixes: d401727ea0d7 ("devtmpfs: don't mix {ramfs,shmem}_fill_super() with mount_single()")
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
drivers/base/devtmpfs.c | 7 +++++++
1 file changed, 7 insertions(+)
(limited to 'drivers/base')
diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c
index 1e2c2d3882e2..f41063ac1aee 100644
--- a/drivers/base/devtmpfs.c
+++ b/drivers/base/devtmpfs.c
@@ -65,8 +65,15 @@ static struct dentry *public_dev_mount(struct file_system_type *fs_type, int fla
const char *dev_name, void *data)
{
struct super_block *s = mnt->mnt_sb;
+ int err;
+
atomic_inc(&s->s_active);
down_write(&s->s_umount);
+ err = reconfigure_single(s, flags, data);
+ if (err < 0) {
+ deactivate_locked_super(s);
+ return ERR_PTR(err);
+ }
return dget(s->s_root);
}
--
cgit