mnt: Refactor fs_fully_visible into mount_too_revealing
Replace the call of fs_fully_visible in do_new_mount from before the
new superblock is allocated with a call of mount_too_revealing after
the superblock is allocated. This winds up being a much better location
for maintainability of the code.
The first change this enables is the replacement of FS_USERNS_VISIBLE
with SB_I_USERNS_VISIBLE. Moving the flag from struct filesystem_type
to sb_iflags on the superblock.
Unfortunately mount_too_revealing fundamentally needs to touch
mnt_flags adding several MNT_LOCKED_XXX flags at the appropriate
times. If the mnt_flags did not need to be touched the code
could be easily moved into the filesystem specific mount code.
Acked-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c
index f3db820..f31e369 100644
--- a/fs/sysfs/mount.c
+++ b/fs/sysfs/mount.c
@@ -42,7 +42,7 @@
kobj_ns_drop(KOBJ_NS_TYPE_NET, ns);
else if (new_sb)
/* Userspace would break if executables appear on sysfs */
- root->d_sb->s_iflags |= SB_I_NOEXEC;
+ root->d_sb->s_iflags |= SB_I_USERNS_VISIBLE | SB_I_NOEXEC;
return root;
}
@@ -59,7 +59,7 @@
.name = "sysfs",
.mount = sysfs_mount,
.kill_sb = sysfs_kill_sb,
- .fs_flags = FS_USERNS_VISIBLE | FS_USERNS_MOUNT,
+ .fs_flags = FS_USERNS_MOUNT,
};
int __init sysfs_init(void)