LXR linux/fs/mount.h

   1/* SPDX-License-Identifier: GPL-2.0 */
   2#include <linux/mount.h>
   3#include <linux/seq_file.h>
   4#include <linux/poll.h>
   5#include <linux/ns_common.h>
   6#include <linux/fs_pin.h>
   7
   8struct mnt_namespace {
   9        atomic_t                count;
  10        struct ns_common        ns;
  11        struct mount *  root;
  12        struct list_head        list;
  13        struct user_namespace   *user_ns;
  14        struct ucounts          *ucounts;
  15        u64                     seq;    /* Sequence number to prevent loops */
  16        wait_queue_head_t poll;
  17        u64 event;
  18        unsigned int            mounts; /* # of mounts in the namespace */
  19        unsigned int            pending_mounts;
  20} __randomize_layout;
  21
  22struct mnt_pcp {
  23        int mnt_count;
  24        int mnt_writers;
  25};
  26
  27struct mountpoint {
  28        struct hlist_node m_hash;
  29        struct dentry *m_dentry;
  30        struct hlist_head m_list;
  31        int m_count;
  32};
  33
  34struct mount {
  35        struct hlist_node mnt_hash;
  36        struct mount *mnt_parent;
  37        struct dentry *mnt_mountpoint;
  38        struct vfsmount mnt;
  39        union {
  40                struct rcu_head mnt_rcu;
  41                struct llist_node mnt_llist;
  42        };
  43#ifdef CONFIG_SMP
  44        struct mnt_pcp __percpu *mnt_pcp;
  45#else
  46        int mnt_count;
  47        int mnt_writers;
  48#endif
  49        struct list_head mnt_mounts;    /* list of children, anchored here */
  50        struct list_head mnt_child;     /* and going through their mnt_child */
  51        struct list_head mnt_instance;  /* mount instance on sb->s_mounts */
  52        const char *mnt_devname;        /* Name of device e.g. /dev/dsk/hda1 */
  53        struct list_head mnt_list;
  54        struct list_head mnt_expire;    /* link in fs-specific expiry list */
  55        struct list_head mnt_share;     /* circular list of shared mounts */
  56        struct list_head mnt_slave_list;/* list of slave mounts */
  57        struct list_head mnt_slave;     /* slave list entry */
  58        struct mount *mnt_master;       /* slave is on master->mnt_slave_list */
  59        struct mnt_namespace *mnt_ns;   /* containing namespace */
  60        struct mountpoint *mnt_mp;      /* where is it mounted */
  61        union {
  62                struct hlist_node mnt_mp_list;  /* list mounts with the same mountpoint */
  63                struct hlist_node mnt_umount;
  64        };
  65        struct list_head mnt_umounting; /* list entry for umount propagation */
  66#ifdef CONFIG_FSNOTIFY
  67        struct fsnotify_mark_connector __rcu *mnt_fsnotify_marks;
  68        __u32 mnt_fsnotify_mask;
  69#endif
  70        int mnt_id;                     /* mount identifier */
  71        int mnt_group_id;               /* peer group identifier */
  72        int mnt_expiry_mark;            /* true if marked for expiry */
  73        struct hlist_head mnt_pins;
  74        struct hlist_head mnt_stuck_children;
  75} __randomize_layout;
  76
  77#define MNT_NS_INTERNAL ERR_PTR(-EINVAL) /* distinct from any mnt_namespace */
  78
  79static inline struct mount *real_mount(struct vfsmount *mnt)
  80{
  81        return container_of(mnt, struct mount, mnt);
  82}
  83
  84static inline int mnt_has_parent(struct mount *mnt)
  85{
  86        return mnt != mnt->mnt_parent;
  87}
  88
  89static inline int is_mounted(struct vfsmount *mnt)
  90{
  91        /* neither detached nor internal? */
  92        return !IS_ERR_OR_NULL(real_mount(mnt)->mnt_ns);
  93}
  94
  95extern struct mount *__lookup_mnt(struct vfsmount *, struct dentry *);
  96
  97extern int __legitimize_mnt(struct vfsmount *, unsigned);
  98extern bool legitimize_mnt(struct vfsmount *, unsigned);
  99
 100static inline bool __path_is_mountpoint(const struct path *path)
 101{
 102        struct mount *m = __lookup_mnt(path->mnt, path->dentry);
 103        return m && likely(!(m->mnt.mnt_flags & MNT_SYNC_UMOUNT));
 104}
 105
 106extern void __detach_mounts(struct dentry *dentry);
 107
 108static inline void detach_mounts(struct dentry *dentry)
 109{
 110        if (!d_mountpoint(dentry))
 111                return;
 112        __detach_mounts(dentry);
 113}
 114
 115static inline void get_mnt_ns(struct mnt_namespace *ns)
 116{
 117        atomic_inc(&ns->count);
 118}
 119
 120extern seqlock_t mount_lock;
 121
 122static inline void lock_mount_hash(void)
 123{
 124        write_seqlock(&mount_lock);
 125}
 126
 127static inline void unlock_mount_hash(void)
 128{
 129        write_sequnlock(&mount_lock);
 130}
 131
 132struct proc_mounts {
 133        struct mnt_namespace *ns;
 134        struct path root;
 135        int (*show)(struct seq_file *, struct vfsmount *);
 136        void *cached_mount;
 137        u64 cached_event;
 138        loff_t cached_index;
 139};
 140
 141extern const struct seq_operations mounts_op;
 142
 143extern bool __is_local_mountpoint(struct dentry *dentry);
 144static inline bool is_local_mountpoint(struct dentry *dentry)
 145{
 146        if (!d_mountpoint(dentry))
 147                return false;
 148
 149        return __is_local_mountpoint(dentry);
 150}
 151
 152static inline bool is_anon_ns(struct mnt_namespace *ns)
 153{
 154        return ns->seq == 0;
 155}
 156