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Commit cc50a07a authored by Eric W. Biederman's avatar Eric W. Biederman
Browse files

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: default avatarSeth Forshee <seth.forshee@canonical.com>
Signed-off-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
parent 67690f93

fs/devpts/inode.c

+2 −1
Original line number Diff line number Diff line
@@ -396,6 +396,7 @@ devpts_fill_super(struct super_block *s, void *data, int silent) 
{

	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 @@ static struct file_system_type devpts_fs_type = { 
	.name		= "devpts",

	.mount		= devpts_mount,

	.kill_sb	= devpts_kill_sb,

	.fs_flags	= FS_USERNS_MOUNT | FS_USERNS_DEV_MOUNT,

	.fs_flags	= FS_USERNS_MOUNT,

};



/*

fs/super.c

+1 −2
Original line number Diff line number Diff line
@@ -206,8 +206,7 @@ static struct super_block *alloc_super(struct file_system_type *type, int flags, 
	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);

include/linux/fs.h

+0 −1
Original line number Diff line number Diff line
@@ -2022,7 +2022,6 @@ struct file_system_type { 
#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 *);