userns: Remove the now unnecessary FS_USERNS_DEV_MOUNT flag
Now that SB_I_NODEV controls the nodev behavior devpts can just clear
this flag during mount. Simplifying the code and making it easier
to audit how the code works. While still preserving the invariant
that s_iflags is only modified during mount.
Acked-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
diff --git a/fs/devpts/inode.c b/fs/devpts/inode.c
index 37c134a..d116453 100644
--- a/fs/devpts/inode.c
+++ b/fs/devpts/inode.c
@@ -396,6 +396,7 @@
{
struct inode *inode;
+ s->s_iflags &= ~SB_I_NODEV;
s->s_blocksize = 1024;
s->s_blocksize_bits = 10;
s->s_magic = DEVPTS_SUPER_MAGIC;
@@ -480,7 +481,7 @@
.name = "devpts",
.mount = devpts_mount,
.kill_sb = devpts_kill_sb,
- .fs_flags = FS_USERNS_MOUNT | FS_USERNS_DEV_MOUNT,
+ .fs_flags = FS_USERNS_MOUNT,
};
/*
diff --git a/fs/super.c b/fs/super.c
index 25cdceed2..37813bf 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -206,8 +206,7 @@
init_waitqueue_head(&s->s_writers.wait_unfrozen);
s->s_bdi = &noop_backing_dev_info;
s->s_flags = flags;
- if ((s->s_user_ns != &init_user_ns) &&
- !(type->fs_flags & FS_USERNS_DEV_MOUNT))
+ if (s->s_user_ns != &init_user_ns)
s->s_iflags |= SB_I_NODEV;
INIT_HLIST_NODE(&s->s_instances);
INIT_HLIST_BL_HEAD(&s->s_anon);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index e059831..375e37f 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2022,7 +2022,6 @@
#define FS_BINARY_MOUNTDATA 2
#define FS_HAS_SUBTYPE 4
#define FS_USERNS_MOUNT 8 /* Can be mounted by userns root */
-#define FS_USERNS_DEV_MOUNT 16 /* A userns mount does not imply MNT_NODEV */
#define FS_RENAME_DOES_D_MOVE 32768 /* FS will handle d_move() during rename() internally. */
struct dentry *(*mount) (struct file_system_type *, int,
const char *, void *);