mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-22 12:14:01 +08:00
98f842e675
Assign a unique proc inode to each namespace, and use that inode number to ensure we only allocate at most one proc inode for every namespace in proc. A single proc inode per namespace allows userspace to test to see if two processes are in the same namespace. This has been a long requested feature and only blocked because a naive implementation would put the id in a global space and would ultimately require having a namespace for the names of namespaces, making migration and certain virtualization tricks impossible. We still don't have per superblock inode numbers for proc, which appears necessary for application unaware checkpoint/restart and migrations (if the application is using namespace file descriptors) but that is now allowd by the design if it becomes important. I have preallocated the ipc and uts initial proc inode numbers so their structures can be statically initialized. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
89 lines
2.3 KiB
C
89 lines
2.3 KiB
C
#include <linux/mount.h>
|
|
#include <linux/seq_file.h>
|
|
#include <linux/poll.h>
|
|
|
|
struct mnt_namespace {
|
|
atomic_t count;
|
|
unsigned int proc_inum;
|
|
struct mount * root;
|
|
struct list_head list;
|
|
struct user_namespace *user_ns;
|
|
u64 seq; /* Sequence number to prevent loops */
|
|
wait_queue_head_t poll;
|
|
int event;
|
|
};
|
|
|
|
struct mnt_pcp {
|
|
int mnt_count;
|
|
int mnt_writers;
|
|
};
|
|
|
|
struct mount {
|
|
struct list_head mnt_hash;
|
|
struct mount *mnt_parent;
|
|
struct dentry *mnt_mountpoint;
|
|
struct vfsmount mnt;
|
|
#ifdef CONFIG_SMP
|
|
struct mnt_pcp __percpu *mnt_pcp;
|
|
#else
|
|
int mnt_count;
|
|
int mnt_writers;
|
|
#endif
|
|
struct list_head mnt_mounts; /* list of children, anchored here */
|
|
struct list_head mnt_child; /* and going through their mnt_child */
|
|
struct list_head mnt_instance; /* mount instance on sb->s_mounts */
|
|
const char *mnt_devname; /* Name of device e.g. /dev/dsk/hda1 */
|
|
struct list_head mnt_list;
|
|
struct list_head mnt_expire; /* link in fs-specific expiry list */
|
|
struct list_head mnt_share; /* circular list of shared mounts */
|
|
struct list_head mnt_slave_list;/* list of slave mounts */
|
|
struct list_head mnt_slave; /* slave list entry */
|
|
struct mount *mnt_master; /* slave is on master->mnt_slave_list */
|
|
struct mnt_namespace *mnt_ns; /* containing namespace */
|
|
#ifdef CONFIG_FSNOTIFY
|
|
struct hlist_head mnt_fsnotify_marks;
|
|
__u32 mnt_fsnotify_mask;
|
|
#endif
|
|
int mnt_id; /* mount identifier */
|
|
int mnt_group_id; /* peer group identifier */
|
|
int mnt_expiry_mark; /* true if marked for expiry */
|
|
int mnt_pinned;
|
|
int mnt_ghosts;
|
|
};
|
|
|
|
#define MNT_NS_INTERNAL ERR_PTR(-EINVAL) /* distinct from any mnt_namespace */
|
|
|
|
static inline struct mount *real_mount(struct vfsmount *mnt)
|
|
{
|
|
return container_of(mnt, struct mount, mnt);
|
|
}
|
|
|
|
static inline int mnt_has_parent(struct mount *mnt)
|
|
{
|
|
return mnt != mnt->mnt_parent;
|
|
}
|
|
|
|
static inline int is_mounted(struct vfsmount *mnt)
|
|
{
|
|
/* neither detached nor internal? */
|
|
return !IS_ERR_OR_NULL(real_mount(mnt));
|
|
}
|
|
|
|
extern struct mount *__lookup_mnt(struct vfsmount *, struct dentry *, int);
|
|
|
|
static inline void get_mnt_ns(struct mnt_namespace *ns)
|
|
{
|
|
atomic_inc(&ns->count);
|
|
}
|
|
|
|
struct proc_mounts {
|
|
struct seq_file m;
|
|
struct mnt_namespace *ns;
|
|
struct path root;
|
|
int (*show)(struct seq_file *, struct vfsmount *);
|
|
};
|
|
|
|
#define proc_mounts(p) (container_of((p), struct proc_mounts, m))
|
|
|
|
extern const struct seq_operations mounts_op;
|