write in 30M

hc

2024-02-20 ea08eeccae9297f7aabd2ef7f0c2517ac4549acc

 kernel/fs/mount.h
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@@ -9,7 +9,13 @@
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 	atomic_t		count;
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 	struct ns_common	ns;
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 	struct mount *	root;
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+	/*
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+	 * Traversal and modification of .list is protected by either
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+	 * - taking namespace_sem for write, OR
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+	 * - taking namespace_sem for read AND taking .ns_lock.
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+	 */
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 	struct list_head	list;
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+	spinlock_t		ns_lock;
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 	struct user_namespace	*user_ns;
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 	struct ucounts		*ucounts;
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 	u64			seq;	/* Sequence number to prevent loops */
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@@ -58,7 +64,10 @@
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 	struct mount *mnt_master;	/* slave is on master->mnt_slave_list */
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 	struct mnt_namespace *mnt_ns;	/* containing namespace */
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 	struct mountpoint *mnt_mp;	/* where is it mounted */
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-	struct hlist_node mnt_mp_list;	/* list mounts with the same mountpoint */
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+	union {
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+		struct hlist_node mnt_mp_list;	/* list mounts with the same mountpoint */
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+		struct hlist_node mnt_umount;
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+	};
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 	struct list_head mnt_umounting; /* list entry for umount propagation */
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 #ifdef CONFIG_FSNOTIFY
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 	struct fsnotify_mark_connector __rcu *mnt_fsnotify_marks;
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@@ -68,8 +77,7 @@
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 	int mnt_group_id;		/* peer group identifier */
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 	int mnt_expiry_mark;		/* true if marked for expiry */
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 	struct hlist_head mnt_pins;
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-	struct fs_pin mnt_umount;
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-	struct dentry *mnt_ex_mountpoint;
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+	struct hlist_head mnt_stuck_children;
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 } __randomize_layout;
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 #define MNT_NS_INTERNAL ERR_PTR(-EINVAL) /* distinct from any mnt_namespace */
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@@ -131,9 +139,7 @@
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 	struct mnt_namespace *ns;
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 	struct path root;
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 	int (*show)(struct seq_file *, struct vfsmount *);
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-	void *cached_mount;
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-	u64 cached_event;
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-	loff_t cached_index;
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+	struct mount cursor;
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 };
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 extern const struct seq_operations mounts_op;
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@@ -146,3 +152,10 @@
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 	return __is_local_mountpoint(dentry);
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 }
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+
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+static inline bool is_anon_ns(struct mnt_namespace *ns)
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+{
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+	return ns->seq == 0;
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+}
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+
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+extern void mnt_cursor_del(struct mnt_namespace *ns, struct mount *cursor);