1 #include "mount.h"
2 #include "VFS.h"
3 #include <common/glib.h>
4 #include <common/string.h>
5
6 static struct List mnt_list_head; // 挂载点链表头
7
8 /**
9 * @brief 初始化mount机制
10 *
11 * @return int 错误码
12 */
mount_init()13 int mount_init()
14 {
15 list_init(&mnt_list_head);
16 return 0;
17 }
18
19 /**
20 * @brief 将new_dentry挂载
21 *
22 * @param old_dentry 挂载点的dentry
23 * @param new_dentry 待挂载的新的dentry(需使用vfs_alloc_dentry来分配)
24 * @return int 错误码
25 */
do_mount(struct vfs_dir_entry_t * old_dentry,struct vfs_dir_entry_t * new_dentry)26 int do_mount(struct vfs_dir_entry_t *old_dentry, struct vfs_dir_entry_t *new_dentry)
27 {
28 struct mountpoint *mp = (struct mountpoint *)kzalloc(sizeof(struct mountpoint), 0);
29 list_init(&mp->mnt_list);
30 mp->dentry = old_dentry;
31 mp->parent_dentry = old_dentry->parent;
32
33 // 拷贝名称
34 strncpy(new_dentry->name, old_dentry->name, old_dentry->name_length);
35 kdebug("new_dentry->name=%s, old_dentry->name=%s, old_dentry->name_length=%d", new_dentry->name, old_dentry->name, old_dentry->name_length);
36
37 new_dentry->d_flags |= VFS_DF_MOUNTED; // 标记新的dentry是一个挂载点
38
39 list_init(&new_dentry->child_node_list);
40 list_init(&new_dentry->subdirs_list);
41 new_dentry->parent = old_dentry->parent;
42
43 // 将新的dentry的list结点替换掉父dentry的列表中的old_dentry的list结点
44 list_replace(&old_dentry->child_node_list, &new_dentry->child_node_list);
45
46 // 后挂载的dentry在链表的末尾（umount恢复的时候需要依赖这个性质）
47 list_append(&mnt_list_head, &mp->mnt_list);
48
49 return 0;
50 }
51
52 /**
53 * @brief 取消某个文件系统的挂载
54 *
55 * @param dentry 对应文件系统的根dentry
56 * @return int 错误码
57 */
do_umount(struct vfs_dir_entry_t * dentry)58 int do_umount(struct vfs_dir_entry_t *dentry)
59 {
60 // todo: 实现umount（主要是结点的恢复问题）
61
62 return 0;
63 }
64
65 /**
66 * @brief 根据mountpoint的父目录dentry查找第一个符合条件的mountpoint结构体
67 *
68 * @param dentry 父dentry
69 * @return struct mountpoint* 第一个符合条件的mountpoint结构体的指针
70 */
mount_find_mnt_list_by_parent(struct vfs_dir_entry_t * dentry)71 struct mountpoint *mount_find_mnt_list_by_parent(struct vfs_dir_entry_t *dentry)
72 {
73 struct List *list = &mnt_list_head;
74 struct mountpoint *ret = NULL;
75 if (list_empty(list))
76 return NULL;
77
78 while (list_next(list) != &mnt_list_head)
79 {
80 list = list_next(list);
81 struct mountpoint *tmp = container_of(list, struct mountpoint, mnt_list);
82 if (dentry == tmp->parent_dentry)
83 return tmp;
84 }
85
86 return NULL;
87 }
88
89 /**
90 * @brief 将挂载点结构体从链表中删除并释放
91 *
92 * @param mp mountpoint结构体
93 * @return int 错误码
94 */
mount_release_mountpoint(struct mountpoint * mp)95 int mount_release_mountpoint(struct mountpoint *mp)
96 {
97 list_del(&mp->mnt_list);
98 return kfree(mp);
99 }