+#include <klibc/string.h>
+#include <lunaix/fs.h>
+#include <lunaix/mm/cake.h>
+#include <lunaix/mm/valloc.h>
+
+#define PATH_DELIM '/'
+#define DNODE_HASHTABLE_BITS 10
+#define DNODE_HASHTABLE_SIZE (1 << DNODE_HASHTABLE_BITS)
+#define DNODE_HASH_MASK (DNODE_HASHTABLE_SIZE - 1)
+#define DNODE_HASHBITS (32 - DNODE_HASHTABLE_BITS)
+
+#define VFS_ETOOLONG -1
+#define VFS_ENOFS -2
+
+static struct cake_pile* dnode_pile;
+static struct cake_pile* inode_pile;
+static struct cake_pile* superblock_pile;
+static struct cake_pile* name_pile;
+
+static struct v_superblock* root_sb;
+static struct hbucket* dnode_cache;
+
+static int fs_id = 0;
+
+struct v_dnode*
+__new_dnode();
+
+void
+__free_dnode(struct v_dnode* dnode);
+
+struct v_superblock*
+__new_superblock();
+
+void
+__free_superblock(struct v_superblock* sb);
+
+void
+vfs_init()
+{
+ // 为他们专门创建一个蛋糕堆，而不使用valloc，这样我们可以最小化内部碎片的产生
+ dnode_pile = cake_new_pile("dnode", sizeof(struct v_dnode), 1, 0);
+ inode_pile = cake_new_pile("inode", sizeof(struct v_inode), 1, 0);
+ name_pile = cake_new_pile("dname", VFS_NAME_MAXLEN, 1, 0);
+ superblock_pile =
+ cake_new_pile("superblock", sizeof(struct v_superblock), 1, 0);
+
+ dnode_cache = valloc(DNODE_HASHTABLE_SIZE * sizeof(struct hbucket));
+
+ // 挂载Lunaix的根文件系统，TwiFS！
+ struct filesystem* rootfs = fsm_get("twifs");
+ root_sb = __new_superblock();
+ rootfs->mount(root_sb, NULL);
+}
+
+inline struct hbucket*
+__dcache_get_bucket(struct v_dnode* parent, unsigned int hash)
+{
+ // 与parent的指针值做加法，来减小碰撞的可能性。
+ hash += (uint32_t)parent;
+ // 确保低位更加随机
+ hash = hash ^ (hash >> DNODE_HASHBITS);
+ return &dnode_cache[hash & DNODE_HASH_MASK];
+}
+
+struct v_dnode*
+vfs_dcache_lookup(struct v_dnode* parent, struct hstr* str)
+{
+ struct hbucket* slot = __dcache_get_bucket(parent, str->hash);
+
+ struct v_dnode *pos, *n;
+ hashtable_bucket_foreach(slot, pos, n, hash_list)
+ {
+ if (pos->name.hash == str->hash) {
+ return pos;
+ }
+ }
+ return NULL;
+}
+
+void
+vfs_dcache_add(struct v_dnode* parent, struct v_dnode* dnode)
+{
+ struct hbucket* bucket = __dcache_get_bucket(parent, dnode->name.hash);
+ hlist_add(&bucket->head, &dnode->hash_list);
+}
+
+int
+vfs_walk(struct v_dnode* start, const char* path, struct v_dnode** dentry)
+{
+ int errno = 0;
+ int i = 0, j = 0;
+
+ if (path[0] == PATH_DELIM) {
+ start = start->super_block->root;
+ i++;
+ }
+
+ struct v_dnode* dnode;
+ struct v_dnode* current_level = start;
+
+ char name_content[VFS_NAME_MAXLEN];
+ struct hstr name = HSTR(name_content, 0);
+
+ char current, lookahead;
+ do {
+ current = path[i++];
+ lookahead = path[i++];
+ if (current != PATH_DELIM) {
+ if (j >= VFS_NAME_MAXLEN - 1) {
+ errno = VFS_ETOOLONG;
+ goto error;
+ }
+ name_content[j++] = current;
+ if (lookahead) {
+ continue;
+ }
+ }
+
+ name_content[j] = 0;
+ hstr_rehash(&name, 32);
+
+ dnode = vfs_dcache_lookup(current_level, &name);
+
+ if (!dnode) {
+ dnode = __new_dnode();
+ strcpy(dnode->name.value, name_content);
+ dnode->name.hash = name.hash;
+ dnode->name.len = j;
+
+ if ((errno =
+ dnode->inode->ops.dir_lookup(current_level->inode, dnode))) {
+ goto error;
+ }
+
+ vfs_dcache_add(current_level, dnode);
+
+ dnode->parent = current_level;
+ llist_append(¤t_level->children, &dnode->siblings);
+ }
+
+ j = 0;
+ current_level = dnode;
+ } while (lookahead);
+
+ *dentry = dnode;
+ return 0;
+
+error:
+ __free_dnode(dnode);
+ return errno;
+}
+
+int
+vfs_mount(const char* fs_name, bdev_t device, struct v_dnode* mnt_point)
+{
+ struct filesystem* fs = fsm_get(fs_name);
+ if (!fs)
+ return VFS_ENOFS;
+ struct v_superblock* sb = __new_superblock();
+ sb->dev = device;
+ sb->fs_id = fs_id++;
+
+ int errno = 0;
+ if (!(errno = fs->mount(sb, mnt_point))) {
+ sb->fs = fs;
+ llist_append(&root_sb->sb_list, &sb->sb_list);
+ }
+
+ return errno;
+}
+
+int
+vfs_unmount(const int fs_id)
+{
+ int errno = 0;
+ struct v_superblock *pos, *n;
+ llist_for_each(pos, n, &root_sb->sb_list, sb_list)
+ {
+ if (pos->fs_id != fs_id) {
+ continue;
+ }
+ if (!(errno = pos->fs->unmount(pos))) {
+ llist_delete(&pos->sb_list);
+ __free_superblock(pos);
+ }
+ break;
+ }
+ return errno;
+}
+
+struct v_superblock*
+__new_superblock()
+{
+ struct v_superblock* sb = cake_grab(superblock_pile);
+ memset(sb, 0, sizeof(*sb));
+ llist_init_head(&sb->sb_list);
+ sb->root = __new_dnode();
+}
+
+void
+__free_superblock(struct v_superblock* sb)
+{
+ __free_dnode(sb->root);
+ cake_release(superblock_pile, sb);
+}
+
+struct v_dnode*
+__new_dnode()
+{
+ struct v_dnode* dnode = cake_grab(dnode_pile);
+ dnode->inode = cake_grab(inode_pile);
+ dnode->name.value = cake_grab(name_pile);
+}
+
+void
+__free_dnode(struct v_dnode* dnode)
+{
+ cake_release(inode_pile, dnode->inode);
+ cake_release(name_pile, dnode->name.value);
+ cake_release(dnode_pile, dnode);
+}
\ No newline at end of file
git://scm.lunaixsky.com / lunaix-os.git / commitdiff