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