Exemple #1
0
/*
 * sfs_getdirentry - according to the iob->io_offset, calculate the dir entry's slot in disk block,
                     get dir entry content from the disk 
 */
static int
sfs_getdirentry(struct inode *node, struct iobuf *iob) {
    struct sfs_disk_entry *entry;
    if ((entry = kmalloc(sizeof(struct sfs_disk_entry))) == NULL) {
        return -E_NO_MEM;
    }

    struct sfs_fs *sfs = fsop_info(vop_fs(node), sfs);
    struct sfs_inode *sin = vop_info(node, sfs_inode);

    int ret, slot;
    off_t offset = iob->io_offset;
    if (offset < 0 || offset % sfs_dentry_size != 0) {
        kfree(entry);
        return -E_INVAL;
    }
    if ((slot = offset / sfs_dentry_size) > sin->din->blocks) {
        kfree(entry);
        return -E_NOENT;
    }
    lock_sin(sin);
    if ((ret = sfs_getdirentry_sub_nolock(sfs, sin, slot, entry)) != 0) {
        unlock_sin(sin);
        goto out;
    }
    unlock_sin(sin);
    ret = iobuf_move(iob, entry->name, sfs_dentry_size, 1, NULL);
out:
    kfree(entry);
    return ret;
}
Exemple #2
0
static int
sfs_namefile(struct inode *node, struct iobuf *iob) {
    struct sfs_disk_entry *entry;
    if (iob->io_resid <= 2 || (entry = kmalloc(sizeof(struct sfs_disk_entry))) == NULL) {
        return -E_NO_MEM;
    }

    struct sfs_fs *sfs = fsop_info(vop_fs(node), sfs);
    struct sfs_inode *sin = vop_info(node, sfs_inode);

    int ret;
    uint32_t ino;
    char *ptr = iob->io_base + iob->io_resid;
    size_t alen, resid = iob->io_resid - 2;
    
    vop_ref_inc(node);
    while ((ino = sin->ino) != SFS_BLKN_ROOT) {
        struct inode *parent;
        if ((ret = sfs_load_parent(sfs, sin, &parent)) != 0) {
            goto failed;
        }
        vop_ref_dec(node);
        
        node = parent, sin = vop_info(node, sfs_inode);
        assert(ino != sin->ino && sin->din->type == SFS_TYPE_DIR);

        if ((ret = trylock_sin(sin)) != 0) {
            goto failed;
        }
        ret = sfs_dirent_findino_nolock(sfs, sin, ino, entry);
        unlock_sin(sin);

        if (ret != 0) {
            goto failed;
        }

        if ((alen = strlen(entry->name) + 1) > resid) {
            goto failed_nomem;
        }
        resid -= alen, ptr -= alen;
        memcpy(ptr, entry->name, alen - 1);
        ptr[alen - 1] = '/';
    }
    vop_ref_dec(node);
    alen = iob->io_resid - resid - 2;
    ptr = memmove(iob->io_base + 1, ptr, alen);
    ptr[-1] = '/', ptr[alen] = '\0';
    iobuf_skip(iob, alen);
    kfree(entry);
    return 0;

failed_nomem:
    ret = -E_NO_MEM;
failed:
    vop_ref_dec(node);
    kfree(entry);
    return ret;
}
Exemple #3
0
static int
pipe_root_create(struct inode *__node, const char *name, bool excl, struct inode **node_store) {
    assert((name[0] == 'r' || name[0] == 'w') && name[1] == '_');
    int ret = 0;
    bool readonly = (name[0] == 'r');
    name += 2;

    struct inode *node[2];
    struct fs *fs = vop_fs(__node);
    struct pipe_fs *pipe = fsop_info(fs, pipe);

    lock_pipe(pipe);

    lookup_pipe_nolock(pipe, name, &node[0], &node[1]);
    if (!readonly) {
        struct inode *tmp = node[0];
        node[0] = node[1], node[1] = tmp;
    }

    if (node[0] != NULL) {
        if (excl) {
            ret = -E_EXISTS, vop_ref_dec(node[0]);
            goto out;
        }
        *node_store = node[0];
        goto out;
    }
    ret = -E_NO_MEM;

    struct pipe_state *state;
    if (node[1] == NULL) {
        if ((state = pipe_state_create()) == NULL) {
            goto out;
        }
    }
    else {
        state = vop_info(node[1], pipe_inode)->state;
        pipe_state_acquire(state);
    }

    struct inode *new_node;
    if ((new_node = pipe_create_inode(fs, name, state, readonly)) == NULL) {
        pipe_state_release(state);
        goto out;
    }

    list_add(&(pipe->pipe_list), &(vop_info(new_node, pipe_inode)->pipe_link));
    ret = 0, *node_store = new_node;

out:
    unlock_pipe(pipe);

    if (node[1] != NULL) {
        vop_ref_dec(node[1]);
    }
    return ret;
}
Exemple #4
0
static int
sfs_reclaim(struct inode *node) {
    struct sfs_fs *sfs = fsop_info(vop_fs(node), sfs);
    struct sfs_inode *sin = vop_info(node, sfs_inode);

    lock_sfs_fs(sfs);

    int ret = -E_BUSY;
    assert(sin->reclaim_count > 0);
    if ((-- sin->reclaim_count) != 0) {
        goto failed_unlock;
    }
    assert(inode_ref_count(node) == 0 && inode_open_count(node) == 0);

    if (sin->din->nlinks == 0) {
        uint32_t nblks;
        for (nblks = sin->din->blocks; nblks != 0; nblks --) {
            sfs_bmap_truncate_nolock(sfs, sin);
        }
    }
    else if (sin->dirty) {
        if ((ret = vop_fsync(node)) != 0) {
            goto failed_unlock;
        }
    }
    
    sfs_remove_links(sin);
    unlock_sfs_fs(sfs);

    if (sin->din->nlinks == 0) {
        sfs_block_free(sfs, sin->ino);
        uint32_t ent;
        if ((ent = sin->din->indirect) != 0) {
            sfs_block_free(sfs, ent);
        }
        if ((ent = sin->din->db_indirect) != 0) {
            int i;
            for (i = 0; i < SFS_BLK_NENTRY; i ++) {
                sfs_bmap_free_sub_nolock(sfs, ent, i);
            }
            sfs_block_free(sfs, ent);
        }
    }
    kfree(sin->din);
    vop_kill(node);
    return 0;

failed_unlock:
    unlock_sfs_fs(sfs);
    return ret;
}
Exemple #5
0
/*
 * sfs_io - Rd/Wr file. the wrapper of sfs_io_nolock
            with lock protect
 */
static inline int
sfs_io(struct inode *node, struct iobuf *iob, bool write) {
    struct sfs_fs *sfs = fsop_info(vop_fs(node), sfs);
    struct sfs_inode *sin = vop_info(node, sfs_inode);
    int ret;
    lock_sin(sin);
    {
        size_t alen = iob->io_resid;
        ret = sfs_io_nolock(sfs, sin, iob->io_base, iob->io_offset, &alen, write);
        if (alen != 0) {
            iobuf_skip(iob, alen);
        }
    }
    unlock_sin(sin);
    return ret;
}
Exemple #6
0
static int
sfs_mkdir(struct inode *node, const char *name) {
    if (strlen(name) > SFS_MAX_FNAME_LEN) {
        return -E_TOO_BIG;
    }
    if (strcmp(name, ".") == 0 || strcmp(name, "..") == 0) {
        return -E_EXISTS;
    }
    struct sfs_fs *sfs = fsop_info(vop_fs(node), sfs);
    struct sfs_inode *sin = vop_info(node, sfs_inode);
    int ret;
    if ((ret = trylock_sin(sin)) == 0) {
        ret = sfs_mkdir_nolock(sfs, sin, name);
        unlock_sin(sin);
    }
    return ret;
}
Exemple #7
0
/*
 * sfs_truncfile : reszie the file with new length
 */
static int
sfs_truncfile(struct inode *node, off_t len) {
    if (len < 0 || len > SFS_MAX_FILE_SIZE) {
        return -E_INVAL;
    }
    struct sfs_fs *sfs = fsop_info(vop_fs(node), sfs);
    struct sfs_inode *sin = vop_info(node, sfs_inode);
    struct sfs_disk_inode *din = sin->din;

    int ret = 0;
	//new number of disk blocks of file
    uint32_t nblks, tblks = ROUNDUP_DIV(len, SFS_BLKSIZE);
    if (din->size == len) {
        assert(tblks == din->blocks);
        return 0;
    }

    lock_sin(sin);
	// old number of disk blocks of file
    nblks = din->blocks;
    if (nblks < tblks) {
		// try to enlarge the file size by add new disk block at the end of file
        while (nblks != tblks) {
            if ((ret = sfs_bmap_load_nolock(sfs, sin, nblks, NULL)) != 0) {
                goto out_unlock;
            }
            nblks ++;
        }
    }
    else if (tblks < nblks) {
		// try to reduce the file size
        while (tblks != nblks) {
            if ((ret = sfs_bmap_truncate_nolock(sfs, sin)) != 0) {
                goto out_unlock;
            }
            nblks --;
        }
    }
    assert(din->blocks == tblks);
    din->size = len;
    sin->dirty = 1;

out_unlock:
    unlock_sin(sin);
    return ret;
}
Exemple #8
0
static int
sfs_truncfile(struct inode *node, off_t len) {
    if (len < 0 || len > SFS_MAX_FILE_SIZE) {
        return -E_INVAL;
    }
    struct sfs_fs *sfs = fsop_info(vop_fs(node), sfs);
    struct sfs_inode *sin = vop_info(node, sfs_inode);
    struct sfs_disk_inode *din = sin->din;
    assert(din->type != SFS_TYPE_DIR);

    int ret = 0;
    uint32_t nblks, tblks = ROUNDUP_DIV(len, SFS_BLKSIZE);
    if (din->fileinfo.size == len) {
        assert(tblks == din->blocks);
        return 0;
    }

    if ((ret = trylock_sin(sin)) != 0) {
        return ret;
    }
    nblks = din->blocks;
    if (nblks < tblks) {
        while (nblks != tblks) {
            if ((ret = sfs_bmap_load_nolock(sfs, sin, nblks, NULL)) != 0) {
                goto out_unlock;
            }
            nblks ++;
        }
    }
    else if (tblks < nblks) {
        while (tblks != nblks) {
            if ((ret = sfs_bmap_truncate_nolock(sfs, sin)) != 0) {
                goto out_unlock;
            }
            nblks --;
        }
    }
    assert(din->blocks == tblks);
    din->fileinfo.size = len;
    sin->dirty = 1;

out_unlock:
    unlock_sin(sin);
    return ret;
}
Exemple #9
0
static int
sfs_lookup(struct inode *node, char *path, struct inode **node_store) {
    struct sfs_fs *sfs = fsop_info(vop_fs(node), sfs);
    assert(*path != '\0' && *path != '/');
    vop_ref_inc(node);
    do {
        struct sfs_inode *sin = vop_info(node, sfs_inode);
        if (sin->din->type != SFS_TYPE_DIR) {
            vop_ref_dec(node);
            return -E_NOTDIR;
        }

        char *subpath;
  next:
        subpath = sfs_lookup_subpath(path);
        if (strcmp(path, ".") == 0) {
            if ((path = subpath) != NULL) {
                goto next;
            }
            break;
        }

        int ret;
        struct inode *subnode;
        if (strcmp(path, "..") == 0) {
            ret = sfs_load_parent(sfs, sin, &subnode);
        }
        else {
            if (strlen(path) > SFS_MAX_FNAME_LEN) {
                vop_ref_dec(node);
                return -E_TOO_BIG;
            }
            ret = sfs_lookup_once(sfs, sin, path, &subnode, NULL);
        }

        vop_ref_dec(node);
        if (ret != 0) {
            return ret;
        }
        node = subnode, path = subpath;
    } while (path != NULL);
    *node_store = node;
    return 0;
}
Exemple #10
0
static int
sfs_getdirentry(struct inode *node, struct iobuf *iob) {
    struct sfs_disk_entry *entry;
    if ((entry = kmalloc(sizeof(struct sfs_disk_entry))) == NULL) {
        return -E_NO_MEM;
    }

    struct sfs_fs *sfs = fsop_info(vop_fs(node), sfs);
    struct sfs_inode *sin = vop_info(node, sfs_inode);

    off_t offset = iob->io_offset;
    if (offset < 0 || offset % sfs_dentry_size != 0) {
        kfree(entry);
        return -E_INVAL;
    }

    int ret, slot = offset / sfs_dentry_size;
    if (slot >= sin->din->dirinfo.slots + 2) {
        kfree(entry);
        return -E_NOENT;
    }
    switch (slot) {
    case 0:
        strcpy(entry->name, ".");
        break;
    case 1:
        strcpy(entry->name, "..");
        break;
    default:
        if ((ret = trylock_sin(sin)) != 0) {
            goto out;
        }
        ret = sfs_getdirentry_sub_nolock(sfs, sin, slot - 2, entry);
        unlock_sin(sin);
        if (ret != 0) {
            goto out;
        }
    }
    ret = iobuf_move(iob, entry->name, sfs_dentry_size, 1, NULL);
out:
    kfree(entry);
    return ret;
}
Exemple #11
0
static int pipe_inode_reclaim(struct inode *node)
{
	struct pipe_inode *pin = vop_info(node, pipe_inode);
	if (pin->name != NULL) {
		struct pipe_fs *pipe = fsop_info(vop_fs(node), pipe);
		lock_pipe(pipe);
		assert(pin->reclaim_count > 0);
		if ((--pin->reclaim_count) != 0 || inode_ref_count(node) != 0) {
			unlock_pipe(pipe);
			return -E_BUSY;
		}
		list_del(&(pin->pipe_link));
		unlock_pipe(pipe);
		kfree(pin->name);
	}
	pipe_state_release(pin->state);
	vop_kill(node);
	return 0;
}
Exemple #12
0
/*
 * sfs_fsync - Force any dirty inode info associated with this file to stable storage.
 */
static int
sfs_fsync(struct inode *node) {
    struct sfs_fs *sfs = fsop_info(vop_fs(node), sfs);
    struct sfs_inode *sin = vop_info(node, sfs_inode);
    int ret = 0;
    if (sin->dirty) {
        lock_sin(sin);
        {
            if (sin->dirty) {
                sin->dirty = 0;
                if ((ret = sfs_wbuf(sfs, sin->din, sizeof(struct sfs_disk_inode), sin->ino, 0)) != 0) {
                    sin->dirty = 1;
                }
            }
        }
        unlock_sin(sin);
    }
    return ret;
}
Exemple #13
0
/*
 * sfs_lookup - Parse path relative to the passed directory
 *              DIR, and hand back the inode for the file it
 *              refers to.
 */
static int
sfs_lookup(struct inode *node, char *path, struct inode **node_store) {
    struct sfs_fs *sfs = fsop_info(vop_fs(node), sfs);
    assert(*path != '\0' && *path != '/');
    vop_ref_inc(node);
    struct sfs_inode *sin = vop_info(node, sfs_inode);
    if (sin->din->type != SFS_TYPE_DIR) {
        vop_ref_dec(node);
        return -E_NOTDIR;
    }
    struct inode *subnode;
    int ret = sfs_lookup_once(sfs, sin, path, &subnode, NULL);

    vop_ref_dec(node);
    if (ret != 0) {
        return ret;
    }
    *node_store = subnode;
    return 0;
}
Exemple #14
0
static int
sfs_fsync(struct inode *node) {
    struct sfs_fs *sfs = fsop_info(vop_fs(node), sfs);
    struct sfs_inode *sin = vop_info(node, sfs_inode);
    if (sin->din->nlinks == 0 || !sin->dirty) {
        return 0;
    }
    int ret;
    if ((ret = trylock_sin(sin)) != 0) {
        return ret;
    }
    if (sin->dirty) {
        sin->dirty = 0;
        if ((ret = sfs_wbuf(sfs, sin->din, sizeof(struct sfs_disk_inode), sin->ino, 0)) != 0) {
            sin->dirty = 1;
        }
    }
    unlock_sin(sin);
    return ret;
}
Exemple #15
0
int pipe_open(struct inode **rnode_store, struct inode **wnode_store)
{
	int ret;
	struct inode *root;
	if ((ret = vfs_get_root("pipe", &root)) != 0) {
		return ret;
	}
	ret = -E_NO_MEM;

	struct pipe_state *state;
	if ((state = pipe_state_create()) == NULL) {
		goto out;
	}

	struct fs *fs = vop_fs(root);
	struct inode *node[2] = { NULL, NULL };
	if ((node[0] = pipe_create_inode(fs, NULL, state, 1)) == NULL) {
		goto failed_cleanup_state;
	}

	pipe_state_acquire(state);
	if ((node[1] = pipe_create_inode(fs, NULL, state, 0)) == NULL) {
		goto failed_cleanup_node0;
	}

	vop_open_inc(node[0]), vop_open_inc(node[1]);

	*rnode_store = node[0];
	*wnode_store = node[1];
	ret = 0;

out:
	vop_ref_dec(root);
	return ret;

failed_cleanup_node0:
	vop_ref_dec(node[0]);
failed_cleanup_state:
	pipe_state_release(state);
	goto out;
}
Exemple #16
0
static int
sfs_link(struct inode *node, const char *name, struct inode *link_node) {
    if (strlen(name) > SFS_MAX_FNAME_LEN) {
        return -E_TOO_BIG;
    }
    if (strcmp(name, ".") == 0 || strcmp(name, "..") == 0) {
        return -E_EXISTS;
    }
    struct sfs_inode *lnksin = vop_info(link_node, sfs_inode);
    if (lnksin->din->type == SFS_TYPE_DIR) {
        return -E_ISDIR;
    }
    struct sfs_fs *sfs = fsop_info(vop_fs(node), sfs);
    struct sfs_inode *sin = vop_info(node, sfs_inode);
    int ret;
    if ((ret = trylock_sin(sin)) == 0) {
        ret = sfs_link_nolock(sfs, sin, lnksin, name);
        unlock_sin(sin);
    }
    return ret;
}
Exemple #17
0
/*
 * sfs_reclaim - Free all resources inode occupied . Called when inode is no longer in use.
 */
static int
sfs_reclaim(struct inode *node) {
    struct sfs_fs *sfs = fsop_info(vop_fs(node), sfs);
    struct sfs_inode *sin = vop_info(node, sfs_inode);

    int  ret = -E_BUSY;
    uint32_t ent;
    lock_sfs_fs(sfs);
    assert(sin->reclaim_count > 0);
    if ((-- sin->reclaim_count) != 0 || inode_ref_count(node) != 0) {
        goto failed_unlock;
    }
    if (sin->din->nlinks == 0) {
        if ((ret = vop_truncate(node, 0)) != 0) {
            goto failed_unlock;
        }
    }
    if (sin->dirty) {
        if ((ret = vop_fsync(node)) != 0) {
            goto failed_unlock;
        }
    }
    sfs_remove_links(sin);
    unlock_sfs_fs(sfs);

    if (sin->din->nlinks == 0) {
        sfs_block_free(sfs, sin->ino);
        if ((ent = sin->din->indirect) != 0) {
            sfs_block_free(sfs, ent);
        }
    }
    kfree(sin->din);
    vop_kill(node);
    return 0;

failed_unlock:
    unlock_sfs_fs(sfs);
    return ret;
}
static int
sfs_getdirentry(struct inode *node, struct iobuf *iob) {
    struct sfs_disk_entry *entry;
    if ((entry = kmalloc(sizeof(struct sfs_disk_entry))) == NULL) {
        // kprintf("%s %s %d -E_NO_MEM\n", __FILE__, __func__, __LINE__);
        return -E_NO_MEM;
    }

    struct sfs_fs *sfs = fsop_info(vop_fs(node), sfs);
    struct sfs_inode *sin = vop_info(node, sfs_inode);

    int ret, slot;
    off_t offset = iob->io_offset;
    if (offset < 0 || offset % sfs_dentry_size != 0) {
        // kprintf("%s %s %d -E_INVAL\n", __FILE__, __func__, __LINE__);
        kfree(entry);
        return -E_INVAL;
    }
    if ((slot = offset / sfs_dentry_size) > sin->din->blocks) {
        // kprintf("%s %s %d -E_NOENT\n", __FILE__, __func__, __LINE__);
        kfree(entry);
        return -E_NOENT;
    }
    lock_sin(sin);
    if ((ret = sfs_getdirentry_sub_nolock(sfs, sin, slot, entry)) != 0) {
        unlock_sin(sin);
        // kprintf("%s %s %d can not find!!! slot is %d\n", __FILE__, __func__, __LINE__, slot);
        goto out;
    }
    unlock_sin(sin);
    // kprintf("sfs_getdirentry\n");
    ret = iobuf_move(iob, entry->name, sfs_dentry_size, 1, NULL);
out:
    kfree(entry);
    return ret;
}
static int
sfs_create(struct inode *node, const char *name, bool excl, struct inode **node_store) {
    // kprintf("ready to create a file\n");
    if (strlen(name) > SFS_MAX_FNAME_LEN) {
        return -1;
    }
    // sfs_create_inode(struct sfs_fs *sfs, struct sfs_disk_inode *din, uint32_t ino, struct inode **node_store)
    struct sfs_fs *sfs = fsop_info(vop_fs(node), sfs);
    struct sfs_inode *sin = vop_info(node, sfs_inode);
    int ret;
    // sfs_create_inode(struct sfs_fs *sfs, struct sfs_disk_inode *din, uint32_t ino, struct inode **node_store)
    struct inode *node_tmp = NULL;
    int empty_slot = -1;
    lock_sfs_fs(sfs);
    // sfs_block_alloc(struct sfs_fs *sfs, uint32_t *ino_store)
    sfs_dirent_search_nolock(sfs, sin, name, node_tmp, NULL, &empty_slot);
    // kprintf("%s\n", __func__);
    if (node_tmp) {
        node_store = node_tmp;
    } else {
        if (empty_slot < 0) {
            kprintf("no slot\n");
            return -1;
        }
        struct sfs_disk_inode *din = alloc_disk_inode(SFS_TYPE_FILE);
        int ino;
        sfs_block_alloc(sfs, &ino);
        // kprintf("%s\n", __func__);
        // if (sfs_block_inuse(sfs, ino)) {
        //     kprintf("be sure use\n");
        // } else {
        //     kprintf("not used\n");
        // }
        sfs_create_inode(sfs, din, ino, &node_tmp);
        ++ (din->__nlinks__);
        sfs_set_links(sfs, vop_info(node_tmp, sfs_inode));
        // kprintf("0x%08x\n", node_tmp);
        // sfs_namefile(struct inode *node, struct iobuf *iob)
        // sfs_dirent_write_nolock(struct sfs_fs *sfs, struct sfs_inode *sin, int slot, uint32_t ino, const char *name)
        sfs_dirent_write_nolock(sfs, sin, empty_slot, ino, name);
        // ++ sin->din->blocks;
        int secno = ram2block(ino);
        swapper_block_changed(secno);
        swapper_block_late_sync(secno);
        // kprintf("sin->ino is %d\n", sin->ino);
        sin->dirty = 1;
        lock_sin(sin);
        {
            if (sin->dirty) {
                sin->dirty = 0;
                if ((ret = sfs_wbuf(sfs, sin->din, sizeof(struct sfs_disk_inode), sin->ino, 0)) != 0) {
                    sin->dirty = 1;
                }
            }
        }
        unlock_sin(sin);
        secno = ram2block(sin->ino);
        swapper_block_changed(secno);
        swapper_block_late_sync(secno);
        vop_info(node_tmp, sfs_inode)->dirty = 1;
        sfs->super_dirty = 1;
        // if ((ret = sfs_bmap_load_nolock(sfs, sin, slot, &ino)) != 0) {
        //     return ret;
        // }
        // assert(sfs_block_inuse(sfs, ino));
        // kprintf("ino is %d\n", ino);
        // kprintf("empty slot is %d\n", empty_slot);
        // kprintf("father ino is %d\n", sin->ino);
        *node_store = node_tmp;
    }
    unlock_sfs_fs(sfs);
    // sfs_create_inode(sfs, struct sfs_disk_inode *din, uint32_t ino, struct inode **node_store)
    return 0;
}
static int
sfs_fsync(struct inode *node) {
    struct sfs_fs *sfs = fsop_info(vop_fs(node), sfs);
    struct sfs_inode *sin = vop_info(node, sfs_inode);
    int ret = 0;


    // if (sfs->super_dirty) {
    //     lock_sfs_fs(sfs);
    //     if (sfs->super_dirty) {
    //         sfs->super_dirty = 0;
    //         if ((ret = sfs_wbuf(sfs, sfs->freemap, sizeof(uint32_t) * 400, 1, 0)) != 0) {
    //             // sfs_wbuf(struct sfs_fs *sfs, void *buf, size_t len, uint32_t blkno, off_t offset)
    //             sfs->super_dirty = 1;
    //         }
    //     }
    //     unlock_sfs_fs(sfs);
    // }
    if (sfs->super_dirty) {
        sfs_sync_super(sfs);
        sfs_sync_freemap(sfs);
        swapper_block_changed(0);
    }

    int secno = -1;

    if (sin->dirty) {
        lock_sin(sin);
        {
            if (sin->dirty) {
                sin->dirty = 0;
                if ((ret = sfs_wbuf(sfs, sin->din, sizeof(struct sfs_disk_inode), sin->ino, 0)) != 0) {
                    sin->dirty = 1;
                }
            }
        }
        // int secno = 0;
        // kprintf("in %s: sin->din is %d sin->ino is %d\n", __func__, sin->din, sin->ino);
        int tmp_din = sin->ino;
        while (tmp_din >= 0) {
            secno += 1; // start from `-1`
            tmp_din -= 32;
        }
        unlock_sin(sin);
    }

    // kprintf("secno is %d sfs->super_dirty is %s\n", secno, sfs->super_dirty ? "true" : "false");
    // assert((secno < 0 && !sfs->super_dirty) || (secno >= 0 && sfs->super_dirty));
    if (secno != 0) {
        // kprintf("sync is secno %d\n", secno);
        if (sfs->super_dirty) {
            sfs->super_dirty = 0;
            swapper_block_sync(0);
        }
        if (secno > 0) {
            swapper_block_sync(secno);
        }
    }
    if (secno == 0) {
        swapper_block_sync(0);
    }
    swapper_block_real_sync();
    // kprintf("super->unused_blocks is %d\n", sfs->super.unused_blocks);
    // uint16_t *begin = (uint16_t *)_initrd_begin;
    // int item = 0;
    // for (item = 0; item < 4000; ++item) {
    //     kprintf("0x%04x ", begin[item]);
    // }
    // kprintf("in %s: %d is %s and addr. of sfs is 0x%08x addr. of freemap is 0x%08x\n",
    // __func__, 436, sfs_block_inuse(sfs, 436)?"used":"free", sfs, sfs->freemap);
    return ret;
}