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0b059f Bob Green 2026-09-02 14:20:10
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# Filesystem Layer
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```mermaid
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---
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title: Filesystem Structures
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---
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classDiagram
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class vmp_t{
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block_device-t *dev_driver
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vfs_fs_t *fs_driver
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char name[16]
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uint8_t block_buff[BLOCK_DEVICE_BLOCK_SIZE]
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unsigned int mounted : 1
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unsigned int read_only : 1
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uint8_t subdev
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union fs_data
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}
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class block_device_t {
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bool_t active
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char name[16]
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uint8_t num_sub_devices
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int (*init)(block_device_t *dev)
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int (*finish)(void)
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int (*read_block)(uint32_t block_num, uint8_t *buff, uint8_t subdev)
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int (*write_block)(uint32_t block_num, uint8_t *buff, uint8_t subdev)
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void *driver_data
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}
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class vfs_fs_t {
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uint8_t type
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int (*handles_path)(const char *pathname)
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char *name
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block_device_t *dev
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vfs_t api
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}
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class fs_data <<union>> {
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ext2_fs_t e2fs
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}
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class vfile_t {
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char path[PATH_MAX]
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bool_t open
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vmp_t *mp
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union file_fs_data
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}
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class file_fs_data <<union>> {
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ext2_file_t e2dir
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}
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class vfs.fs {
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vmp_t *(*mount)(vmp_t *mp)
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int (*unmount)(vmp_t *mp)
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int (*open)(vfile_t *pwd, const char *fname)
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int (*read)(vfile_t *file, char *buf, size_t n_bytes)
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int (*write)(vfile_t *file, const char *buf, size_t n_bytes)
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int (*close)(vfile_t *file)
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}
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class vfs.chardev {
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}
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block_device_t <|-- vmp_t
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vfs_fs_t <|-- vmp_t
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file_fs_data <|-- vfile_t
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```
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Another attempt:
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```mermaid
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erDiagram
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direction BT
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vmp_t:::fs ||--|| ORDER : places
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vmp_t {
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block_device-t *dev_driver
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vfs_fs_t *fs_driver
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char name[16]
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uint8_t block_buff[BLOCK_DEVICE_BLOCK_SIZE]
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unsigned int mounted
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unsigned int read_only
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uint8_t subdev
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union fs_data
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}
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ORDER {
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int orderNumber
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string deliveryAddress
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}
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vfile_t {
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char path[PATH_MAX]
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bool_t open
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vmp_t *mp
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union file_fs_data
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}
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classDef fs fill:#08d,stroke:#333,stroke-width:4px
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```
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> [!NOTE]
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> This diagram is evolving as I am in the process of implementing
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> the code for this. Anything could change, so come back often.