From: NeilBrown neilb@suse.de
commit a6097180d884ddab769fb25588ea8598589c218c upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/base/devtmpfs.c | 8 ++++++++ fs/super.c | 4 ++-- include/linux/fs_context.h | 2 ++ 3 files changed, 12 insertions(+), 2 deletions(-)
--- a/drivers/base/devtmpfs.c +++ b/drivers/base/devtmpfs.c @@ -25,6 +25,7 @@ #include <linux/sched.h> #include <linux/slab.h> #include <linux/kthread.h> +#include <linux/fs_context.h> #include <uapi/linux/mount.h> #include "base.h"
@@ -62,8 +63,15 @@ static struct dentry *public_dev_mount(s 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); }
--- a/fs/super.c +++ b/fs/super.c @@ -1470,8 +1470,8 @@ struct dentry *mount_nodev(struct file_s } EXPORT_SYMBOL(mount_nodev);
-static int reconfigure_single(struct super_block *s, - int flags, void *data) +int reconfigure_single(struct super_block *s, + int flags, void *data) { struct fs_context *fc; int ret; --- a/include/linux/fs_context.h +++ b/include/linux/fs_context.h @@ -135,6 +135,8 @@ extern int generic_parse_monolithic(stru extern int vfs_get_tree(struct fs_context *fc); extern void put_fs_context(struct fs_context *fc); extern void fc_drop_locked(struct fs_context *fc); +int reconfigure_single(struct super_block *s, + int flags, void *data);
/* * sget() wrappers to be called from the ->get_tree() op.