Import changeset

1 files changed, 73 insertions, 0 deletions

diff --git a/include/linux/fs_struct.h b/include/linux/fs_struct.h
new file mode 100644
index 000000000000..3d2df3cf4202
--- /dev/null
+++ b/include/linux/fs_struct.h
@@ -0,0 +1,73 @@
+#ifndef _LINUX_FS_STRUCT_H
+#define _LINUX_FS_STRUCT_H
+#ifdef __KERNEL__
+
+struct fs_struct {
+	atomic_t count;
+	rwlock_t lock;
+	int umask;
+	struct dentry * root, * pwd, * altroot;
+	struct vfsmount * rootmnt, * pwdmnt, * altrootmnt;
+};
+
+#define INIT_FS { \
+	ATOMIC_INIT(1), \
+	RW_LOCK_UNLOCKED, \
+	0022, \
+	NULL, NULL, NULL, NULL, NULL, NULL \
+}
+
+extern void exit_fs(struct task_struct *);
+extern void set_fs_altroot(void);
+
+/*
+ * Replace the fs->{rootmnt,root} with {mnt,dentry}. Put the old values.
+ * It can block. Requires the big lock held.
+ */
+
+static inline void set_fs_root(struct fs_struct *fs,
+	struct vfsmount *mnt,
+	struct dentry *dentry)
+{
+	struct dentry *old_root;
+	struct vfsmount *old_rootmnt;
+	write_lock(&fs->lock);
+	old_root = fs->root;
+	old_rootmnt = fs->rootmnt;
+	fs->rootmnt = mntget(mnt);
+	fs->root = dget(dentry);
+	write_unlock(&fs->lock);
+	if (old_root) {
+		dput(old_root);
+		mntput(old_rootmnt);
+	}
+}
+
+/*
+ * Replace the fs->{pwdmnt,pwd} with {mnt,dentry}. Put the old values.
+ * It can block. Requires the big lock held.
+ */
+
+static inline void set_fs_pwd(struct fs_struct *fs,
+	struct vfsmount *mnt,
+	struct dentry *dentry)
+{
+	struct dentry *old_pwd;
+	struct vfsmount *old_pwdmnt;
+	write_lock(&fs->lock);
+	old_pwd = fs->pwd;
+	old_pwdmnt = fs->pwdmnt;
+	fs->pwdmnt = mntget(mnt);
+	fs->pwd = dget(dentry);
+	write_unlock(&fs->lock);
+	if (old_pwd) {
+		dput(old_pwd);
+		mntput(old_pwdmnt);
+	}
+}
+
+struct fs_struct *copy_fs_struct(struct fs_struct *old);
+void put_fs_struct(struct fs_struct *fs);
+
+#endif
+#endif