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Diffstat (limited to '')
| -rw-r--r-- | fs/mount.h | 161 |
1 files changed, 161 insertions, 0 deletions
diff --git a/fs/mount.h b/fs/mount.h new file mode 100644 index 000000000..c7abb7b39 --- /dev/null +++ b/fs/mount.h @@ -0,0 +1,161 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#include <linux/mount.h> +#include <linux/seq_file.h> +#include <linux/poll.h> +#include <linux/ns_common.h> +#include <linux/fs_pin.h> + +struct mnt_namespace { + atomic_t count; + struct ns_common ns; + struct mount * root; + /* + * Traversal and modification of .list is protected by either + * - taking namespace_sem for write, OR + * - taking namespace_sem for read AND taking .ns_lock. + */ + struct list_head list; + spinlock_t ns_lock; + struct user_namespace *user_ns; + struct ucounts *ucounts; + u64 seq; /* Sequence number to prevent loops */ + wait_queue_head_t poll; + u64 event; + unsigned int mounts; /* # of mounts in the namespace */ + unsigned int pending_mounts; +} __randomize_layout; + +struct mnt_pcp { + int mnt_count; + int mnt_writers; +}; + +struct mountpoint { + struct hlist_node m_hash; + struct dentry *m_dentry; + struct hlist_head m_list; + int m_count; +}; + +struct mount { + struct hlist_node mnt_hash; + struct mount *mnt_parent; + struct dentry *mnt_mountpoint; + struct vfsmount mnt; + union { + struct rcu_head mnt_rcu; + struct llist_node mnt_llist; + }; +#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 */ + struct mountpoint *mnt_mp; /* where is it mounted */ + union { + struct hlist_node mnt_mp_list; /* list mounts with the same mountpoint */ + struct hlist_node mnt_umount; + }; + struct list_head mnt_umounting; /* list entry for umount propagation */ +#ifdef CONFIG_FSNOTIFY + struct fsnotify_mark_connector __rcu *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 */ + struct hlist_head mnt_pins; + struct hlist_head mnt_stuck_children; +} __randomize_layout; + +#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)->mnt_ns); +} + +extern struct mount *__lookup_mnt(struct vfsmount *, struct dentry *); + +extern int __legitimize_mnt(struct vfsmount *, unsigned); +extern bool legitimize_mnt(struct vfsmount *, unsigned); + +static inline bool __path_is_mountpoint(const struct path *path) +{ + struct mount *m = __lookup_mnt(path->mnt, path->dentry); + return m && likely(!(m->mnt.mnt_flags & MNT_SYNC_UMOUNT)); +} + +extern void __detach_mounts(struct dentry *dentry); + +static inline void detach_mounts(struct dentry *dentry) +{ + if (!d_mountpoint(dentry)) + return; + __detach_mounts(dentry); +} + +static inline void get_mnt_ns(struct mnt_namespace *ns) +{ + atomic_inc(&ns->count); +} + +extern seqlock_t mount_lock; + +static inline void lock_mount_hash(void) +{ + write_seqlock(&mount_lock); +} + +static inline void unlock_mount_hash(void) +{ + write_sequnlock(&mount_lock); +} + +struct proc_mounts { + struct mnt_namespace *ns; + struct path root; + int (*show)(struct seq_file *, struct vfsmount *); + struct mount cursor; +}; + +extern const struct seq_operations mounts_op; + +extern bool __is_local_mountpoint(struct dentry *dentry); +static inline bool is_local_mountpoint(struct dentry *dentry) +{ + if (!d_mountpoint(dentry)) + return false; + + return __is_local_mountpoint(dentry); +} + +static inline bool is_anon_ns(struct mnt_namespace *ns) +{ + return ns->seq == 0; +} + +extern void mnt_cursor_del(struct mnt_namespace *ns, struct mount *cursor); |