fs/mount.h

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