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authorEric W. Biederman <ebiederm@xmission.com>2015-05-08 23:22:29 -0500
committerEric W. Biederman <ebiederm@xmission.com>2015-05-13 21:44:11 -0500
commit1b852bceb0d111e510d1a15826ecc4a19358d512 (patch)
treeb7a6b015d68f3ad25f79d7197690a29e08f0e21c /include/linux/fs.h
parent7e96c1b0e0f495c5a7450dc4aa7c9a24ba4305bd (diff)
downloadlwn-1b852bceb0d111e510d1a15826ecc4a19358d512.tar.gz
lwn-1b852bceb0d111e510d1a15826ecc4a19358d512.zip
mnt: Refactor the logic for mounting sysfs and proc in a user namespace
Fresh mounts of proc and sysfs are a very special case that works very much like a bind mount. Unfortunately the current structure can not preserve the MNT_LOCK... mount flags. Therefore refactor the logic into a form that can be modified to preserve those lock bits. Add a new filesystem flag FS_USERNS_VISIBLE that requires some mount of the filesystem be fully visible in the current mount namespace, before the filesystem may be mounted. Move the logic for calling fs_fully_visible from proc and sysfs into fs/namespace.c where it has greater access to mount namespace state. Cc: stable@vger.kernel.org Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Diffstat (limited to 'include/linux/fs.h')
-rw-r--r--include/linux/fs.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 35ec87e490b1..2d24eeb8e59c 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1897,6 +1897,7 @@ struct file_system_type {
#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_USERNS_VISIBLE 32 /* FS must already be visible */
#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 *);
@@ -1984,7 +1985,6 @@ extern int vfs_ustat(dev_t, struct kstatfs *);
extern int freeze_super(struct super_block *super);
extern int thaw_super(struct super_block *super);
extern bool our_mnt(struct vfsmount *mnt);
-extern bool fs_fully_visible(struct file_system_type *);
extern int current_umask(void);