From 0084fefe2960b3a0c6482558272ee6372c75e3d4 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Mon, 17 Jan 2022 09:07:26 +1100 Subject: [PATCH] devtmpfs regression fix: reconfigure on each mount 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 Cc: Al Viro Signed-off-by: NeilBrown Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- drivers/base/devtmpfs.c | 7 +++++++ fs/super.c | 4 ++-- include/linux/fs_context.h | 2 ++ 3 files changed, 11 insertions(+), 2 deletions(-) diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c index a71d141..b5cbaa6 100644 --- a/drivers/base/devtmpfs.c +++ b/drivers/base/devtmpfs.c @@ -59,8 +59,15 @@ 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); } diff --git a/fs/super.c b/fs/super.c index 98bb062..20f17078 100644 --- a/fs/super.c +++ b/fs/super.c @@ -1472,8 +1472,8 @@ struct dentry *mount_nodev(struct file_system_type *fs_type, } 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; diff --git a/include/linux/fs_context.h b/include/linux/fs_context.h index 5b44b01..e869ce3 100644 --- a/include/linux/fs_context.h +++ b/include/linux/fs_context.h @@ -140,6 +140,8 @@ extern int generic_parse_monolithic(struct fs_context *fc, void *data); 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. -- 2.7.4