ch8-pv1-the-virtual-filesystem
- 2. 2 ● FIlesystems ● VFS ● Rootfs ● Dir/File Operations
- 3. 4 Filesystems msdos disk vfat ntfs ext4 cd-rom iso9660 usb vfat emmc ext4 ram network cifs nfs procfs sysfs pipefs sockfs ramfs tmpfs *. meta/data layout *. file name length *. date/time *. max partition/file size *. journal *. block allocation *. fragmentation *. ... storage
- 5. 6 vfs emmc ext4 file directory link char block fifo sock usb vfat file directory ram tmpfs file directory link char block fifo sock sysfs file(attr) directory link bin_attr sockfs file VFS fop iop inode dentry file name ext4mount address space p pp p p p p p meta data
- 6. 7 VFS / dev init proc system sysdata bbb cccaaa C eee fffddd D linux windows
- 7. 8 VFS “/”d rootfsm d “dev” d “init” d “proc” d “system” d “sys”d “data
- 8. 9 VFS “/”d rootfsm d “dev” d “init” d “proc” d “system” d “sys” d “console” d “/” tmpfsm d “pts” d “data d “/” ext4m d “/” procm d “/” ext4m d “/” sysfsm d “/” devptsm d “bin” d “sh”
- 9. 10 VFS d “init” fop iop i getattr( ) setattr( ) mmap( ) aio_write( ) write( ) aio_read( ) fsync( ) llseek( ) read( ) file@rootfs filesystem + file type
- 10. 11 VFS d “init” fop iop i symlink( ) unlink( ) link( ) lookup( ) mkdir( ) rmdir( ) create( ) fsync( ) read( ) llseek( ) release( ) open( ) dir@rootfs filesystem + file type mknod( ) rename( )
- 11. 14 Rootfs kernel rootfs uImage initramfs partition b partition a SN kernel ramdisk boot.img initramfs partition a ANAN kernel rootfs uImage initramfs dram bring up SN: 各自產生 , 各佔一個 partition AN: 各自產生 , 合併檔案 & 佔一個 partition bring up: 同時產生 ( 單一檔案 ), 載入 dram
- 13. 16 Rootfs kernel ramdisk boot.img initramfs data init init.rc proc sys system sbin adbd healthd root devconsole first userspace process standard in standard out standard err root mount run commands AN
- 15. 18 Rootfs fopiopi “/”d rootfsm fopiopi d “dev” fopiopi d “console” 1. 掛載 rootfs 2. 根據 initramfs 建檔
- 16. 19 Rootfs fopiopi “/”d rootfsm fopiopi d “dev” fopiopi d “init” fopiopi d “proc” fopiopi d “system” fopiopi d “sys” fopiopi d “console” fopiopi d “data 1. 掛載 rootfs 2. 根據 initramfs 建檔 3. 根據 ramdisk 建檔
- 17. 20 Rootfs fopiopi “/”d rootfsm fopiopi d “dev” fopiopi d “init” fopiopi d “proc” fopiopi d “system” fopiopi d “sys” fopiopi d “console” fopiopi d “data 1. 掛載 rootfs 2. 根據 initramfs 建檔 3. 根據 ramdisk 建檔 4. init 預設行為
- 18. 21 Rootfs fopiopi “/”d rootfsm fopiopi d “dev” fopiopi d “init” fopiopi d “proc” fopiopi d “system” fopiopi d “sys” fopiopi d “console” fopiopi d “/” tmpfsm fopiopi d “data 1. 掛載 rootfs 2. 根據 initramfs 建檔 3. 根據 ramdisk 建檔 4. init 預設行為 a. mount tmpfs
- 19. 23 Rootfs fopiopi “/”d rootfsm fopiopi d “dev” fopiopi d “init” fopiopi d “proc” fopiopi d “system” fopiopi d “sys” fopiopi d “console” fopiopi d “/” tmpfsm fopiopi d “pts” fopiopi d “data 1. 掛載 rootfs 2. 根據 initramfs 建檔 3. 根據 ramdisk 建檔 4. init 預設行為 a. mount tmpfs b. mkdir pts
- 20. 24 Rootfs fopiopi “/”d rootfsm fopiopi d “dev” fopiopi d “init” fopiopi d “proc” fopiopi d “system” fopiopi d “sys” fopiopi d “console” fopiopi d “/” tmpfsm fopiopi d “pts” fopiopi d “data fopiopi d “/” devptsm 1. 掛載 rootfs 2. 根據 initramfs 建檔 3. 根據 ramdisk 建檔 4. init 預設行為 a. mount tmpfs b. mkdir pts c. mount devpts
- 21. 25 Rootfs fopiopi “/”d rootfsm fopiopi d “dev” fopiopi d “init” fopiopi d “proc” fopiopi d “system” fopiopi d “sys” fopiopi d “console” fopiopi d “/” tmpfsm fopiopi d “pts” fopiopi d “data fopiopi d “/” procm fopiopi d “/” devptsm 1. 掛載 rootfs 2. 根據 initramfs 建檔 3. 根據 ramdisk 建檔 4. init 預設行為 a. mount tmpfs b. mkdir pts c. mount devpts d. mount proc
- 22. 26 Rootfs fopiopi “/”d rootfsm fopiopi d “dev” fopiopi d “init” fopiopi d “proc” fopiopi d “system” fopiopi d “sys” fopiopi d “console” fopiopi d “/” tmpfsm fopiopi d “pts” fopiopi d “data fopiopi d “/” procm fopiopi d “/” sysfsm fopiopi d “/” devptsm 1. 掛載 rootfs 2. 根據 initramfs 建檔 3. 根據 ramdisk 建檔 4. init 預設行為 a. mount tmpfs b. mkdir pts c. mount devpts d. mount proc e. mount sysfs
- 23. 27 Rootfs fopiopi “/”d rootfsm fopiopi d “dev” fopiopi d “init” fopiopi d “proc” fopiopi d “system” fopiopi d “sys” fopiopi d “console” fopiopi d “/” tmpfsm fopiopi d “pts” fopiopi d “data fopiopi d “/” procm fopiopi d “/” sysfsm fopiopi d “/” devptsm 1. 掛載 rootfs 2. 根據 initramfs 建檔 3. 根據 ramdisk 建檔 4. init 預設行為 a. mount tmpfs b. mkdir pts c. mount devpts d. mount proc e. mount sysfs 5. init 根據 init.rc 行為 “init.rc”
- 24. 28 Rootfs fopiopi “/”d rootfsm fopiopi d “dev” fopiopi d “init” fopiopi d “proc” fopiopi d “system” fopiopi d “sys” fopiopi d “console” fopiopi d “/” tmpfsm fopiopi d “pts” fopiopi d “data fopiopi d “/” ext4m fopiopi d “/” procm fopiopi d “/” sysfsm fopiopi d “/” devptsm 1. 掛載 rootfs 2. 根據 initramfs 建檔 3. 根據 ramdisk 建檔 4. init 預設行為 a. mount tmpfs b. mkdir pts c. mount devpts d. mount proc e. mount sysfs 5. init 根據 init.rc 行為 a. mount data
- 25. 29 Rootfs fopiopi “/”d rootfsm fopiopi d “dev” fopiopi d “init” fopiopi d “proc” fopiopi d “system” fopiopi d “sys” fopiopi d “console” fopiopi d “/” tmpfsm fopiopi d “pts” fopiopi d “data fopiopi d “/” ext4m fopiopi d “/” procm fopiopi d “/” ext4m fopiopi d “/” sysfsm fopiopi d “/” devptsm 1. 掛載 rootfs 2. 根據 initramfs 建檔 3. 根據 ramdisk 建檔 4. init 預設行為 a. mount tmpfs b. mkdir pts c. mount devpts d. mount proc e. mount sysfs 5. init 根據 init.rc 行為 a. mount data b. mount system
- 26. 30 Rootfs fopiopi “/”d rootfsm fopiopi d “dev” fopiopi d “init” fopiopi d “proc” fopiopi d “system” fopiopi d “sys” fopiopi d “console” fopiopi d “/” tmpfsm fopiopi d “pts” fopiopi d “data fopiopi d “/” ext4m fopiopi d “/” procm fopiopi d “/” ext4m fopiopi d “/” sysfsm fopiopi d “/” devptsm app bin xbin sh su 1. 掛載 rootfs 2. 根據 initramfs 建檔 3. 根據 ramdisk 建檔 4. init 預設行為 a. mount tmpfs b. mkdir pts c. mount devpts d. mount proc e. mount sysfs 5. init 根據 init.rc 行為 a. mount data b. mount system
- 27. 31 Rootfs fopiopi “/”d rootfsm fopiopi d “dev” fopiopi d “init” fopiopi d “proc” fopiopi d “system” fopiopi d “sys” fopiopi d “console” fopiopi d “/” tmpfsm fopiopi d “pts” fopiopi d “data fopiopi d “/” ext4m fopiopi d “/” procm fopiopi d “/” ext4m fopiopi d “/” sysfsm fopiopi d “/” devptsm fopiopi d “bin” fopiopi d “sh” app xbin 1. 掛載 rootfs 2. 根據 initramfs 建檔 3. 根據 ramdisk 建檔 4. init 預設行為 a. mount tmpfs b. mkdir pts c. mount devpts d. mount proc e. mount sysfs 5. init 根據 init.rc 行為 a. mount data b. mount system c. /bin/sh su kernel 行為 userspace 行為
- 28. 32 Rootfs fopiopi “/”d rootfsm fopiopi d “dev” fopiopi d “init” fopiopi d “proc” fopiopi d “system” fopiopi d “sys” fopiopi d “console” fopiopi d “/” tmpfsm fopiopi d “pts” fopiopi d “data fopiopi d “/” ext4m fopiopi d “/” procm fopiopi d “/” ext4m fopiopi d “/” sysfsm fopiopi d “/” devptsm fopiopi d “bin” fopiopi d “sh” app xbin 1. 掛載 rootfs 2. 根據 initramfs 建檔 3. 根據 ramdisk 建檔 4. init 預設行為 a. mount tmpfs b. mkdir pts c. mount devpts d. mount proc e. mount sysfs 5. init 根據 init.rc 行為 a. mount data b. mount system c. /bin/sh su fopiopi d “/” debugfsm fopiopi d “/” devtmpfsm fopiopi d “/” sockfsm fopiopi d “/” pipefsm
- 30. 34 Mount fopiopi “/”d rootfsm fopiopi d “dev” tmpfsm 1. 建立 mount 2. 建立 root inode fopiopi
- 31. 35 Mount fopiopi “/”d rootfsm fopiopi d “dev” tmpfsm 1. 建立 mount 2. 建立 root inode 3. 建立 root dentry “/” fopiopi d “/”
- 32. 36 Mount fopiopi “/”d rootfsm fopiopi d “dev” tmpfsm 1. 建立 mount 2. 建立 root inode 3. 建立 root dentry “/” 4. 紀錄 parent mount & mount point(dentry) fopiopi d “/”
- 33. 37 Lookup fopiopi “/”d rootfsm fopiopi d “console” fopiopi d “dev” *. task pwd 初始指向 root dentry *. cd dev/console/../.. pwd
- 34. 38 Lookup fopiopi “/”d rootfsm fopiopi d “console” fopiopi d “dev” *. task pwd 初始指向 root dentry *. cd dev/console/../.. 1. 往下 , 查表 , “/” dentry + child string “dev” 獲取” dev” dentry pwd dentry hashtable dev/ “dev”
- 35. 39 Lookup fopiopi “/”d rootfsm fopiopi d “console” fopiopi d “dev” pwd *. task pwd 初始指向 root dentry *. cd dev/console/../.. 1. 往下 , 查表 , “/” dentry + child string “dev” 獲取” dev” dentry 2. 往下 , 查表 , “dev” dentry + child string “console” 獲取” console” dentry dentry hashtable dev “console” console
- 36. 40 Lookup fopiopi “/”d rootfsm fopiopi d “console” fopiopi d “dev” pwd *. task pwd 初始指向 root dentry *. cd dev/console/../.. 1. 往下 , 查表 , “/” dentry + child string “dev” 獲取” dev” dentry 2. 往下 , 查表 , “dev” dentry + child string “console” 獲取” console” dentry 3. 往上 , 指標
- 37. 41 Lookup fopiopi “/”d rootfsm fopiopi d “console” fopiopi d “dev” pwd *. task pwd 初始指向 root dentry *. cd dev/console/../.. 1. 往下 , 查表 , “/” dentry + child string “dev” 獲取” dev” dentry 2. 往下 , 查表 , “dev” dentry + child string “console” 獲取” console” dentry 3. 往上 , 指標 4. 往上 , 指標
- 38. 42 Lookup fopiopi “/”d rootfsm fopiopi d “console” fopiopi d “dev” fopiopi d “/” tmpfsm fopiopi d “pts” fopiopi d “/” devptsm *. task pwd 初始指向 root dentry *. cd dev/pts/../.. pwd
- 39. 43 Lookup fopiopi “/”d rootfsm fopiopi d “console” fopiopi d “dev” fopiopi d “/” tmpfsm fopiopi d “pts” fopiopi d “/” devptsm *. task pwd 初始指向 root dentry *. cd dev/pts/../.. 1.1. 往下 , 查表 , 獲取” dev” dentry pwd dentry hashtable dev/ “dev”
- 40. 44 Lookup fopiopi “/”d rootfsm fopiopi d “console” fopiopi d “dev” fopiopi d “/” tmpfsm fopiopi d “pts” fopiopi d “/” devptsm *. task pwd 初始指向 root dentry *. cd dev/pts/../.. 1.1. 往下 , 查表 , 獲取” dev” dentry 1.2. follow mount, 查表 , rootfs mount + “dev” dentry 獲取 tmpfs mount( 獲取 root dentry) pwd dentry hashtable dev mount hashtable dev rootfs tmpfs / “dev”
- 41. 45 Lookup fopiopi “/”d rootfsm fopiopi d “console” fopiopi d “dev” fopiopi d “/” tmpfsm fopiopi d “pts” fopiopi d “/” devptsm *. task pwd 初始指向 root dentry *. cd dev/pts/../.. 1.1. 往下 , 查表 , 獲取” dev” dentry 1.2. follow mount, 查表 , rootfs mount + “dev” dentry 獲取 tmpfs mount( 獲取 root dentry) 2.1. 往下 , 查表 , 獲取” pts” dentry pwd dentry hashtable pts/ “pts”
- 42. 46 Lookup fopiopi “/”d rootfsm fopiopi d “console” fopiopi d “dev” fopiopi d “/” tmpfsm fopiopi d “pts” fopiopi d “/” devptsm *. task pwd 初始指向 root dentry *. cd dev/pts/../.. 1.1. 往下 , 查表 , 獲取” dev” dentry 1.2. follow mount, 查表 , rootfs mount + “dev” dentry 獲取 tmpfs mount( 獲取 root dentry) 2.1. 往下 , 查表 , 獲取” pts” dentry 2.2. follow mount, 查表 , tmpfs mount + “pts” dentry 獲取 devpts mount( 獲取 root dentry) pwd mount hashtable pts tmpfs devpts dentry hashtable pts/ “pts”
- 43. 47 Lookup fopiopi “/”d rootfsm fopiopi d “console” fopiopi d “dev” fopiopi d “/” tmpfsm fopiopi d “pts” fopiopi d “/” devptsm *. task pwd 初始指向 root dentry *. cd dev/pts/../.. 1.1. 往下 , 查表 , 獲取” dev” dentry 1.2. follow mount, 查表 , rootfs mount + “dev” dentry 獲取 tmpfs mount( 獲取 root dentry) 2.1. 往下 , 查表 , 獲取” pts” dentry 2.2. follow mount, 查表 , tmpfs mount + “pts” dentry 獲取 devpts mount( 獲取 root dentry) 3.1. follow up, 指標 (to mount point) pwd
- 44. 48 Lookup fopiopi “/”d rootfsm fopiopi d “console” fopiopi d “dev” fopiopi d “/” tmpfsm fopiopi d “pts” fopiopi d “/” devptsm *. task pwd 初始指向 root dentry *. cd dev/pts/../.. 1.1. 往下 , 查表 , 獲取” dev” dentry 1.2. follow mount, 查表 , rootfs mount + “dev” dentry 獲取 tmpfs mount( 獲取 root dentry) 2.1. 往下 , 查表 , 獲取” pts” dentry 2.2. follow mount, 查表 , tmpfs mount + “pts” dentry 獲取 devpts mount( 獲取 root dentry) 3.1. follow up, 指標 (to mount point) 3.2. 往上 , 指標 (to parent dentry) pwd
- 45. 49 Lookup fopiopi “/”d rootfsm fopiopi d “console” fopiopi d “dev” fopiopi d “/” tmpfsm fopiopi d “pts” fopiopi d “/” devptsm *. task pwd 初始指向 root dentry *. cd dev/pts/../.. 1.1. 往下 , 查表 , 獲取” dev” dentry 1.2. follow mount, 查表 , rootfs mount + “dev” dentry 獲取 tmpfs mount( 獲取 root dentry) 2.1. 往下 , 查表 , 獲取” pts” dentry 2.2. follow mount, 查表 , tmpfs mount + “pts” dentry 獲取 devpts mount( 獲取 root dentry) 3.1. follow up, 指標 (to mount point) 3.2. 往上 , 指標 (to parent dentry) 4.1. follow up, 指標 (to mount point) pwd
- 46. 50 Lookup fopiopi “/”d rootfsm fopiopi d “console” fopiopi d “dev” fopiopi d “/” tmpfsm fopiopi d “pts” fopiopi d “/” devptsm *. task pwd 初始指向 root dentry *. cd dev/pts/../.. 1.1. 往下 , 查表 , 獲取” dev” dentry 1.2. follow mount, 查表 , rootfs mount + “dev” dentry 獲取 tmpfs mount( 獲取 root dentry) 2.1. 往下 , 查表 , 獲取” pts” dentry 2.2. follow mount, 查表 , tmpfs mount + “pts” dentry 獲取 devpts mount( 獲取 root dentry) 3.1. follow up, 指標 (to mount point) 3.2. 往上 , 指標 (to parent dentry) 4.1. follow up, 指標 (to mount point) 4.2. 往上 , 指標 (to parent dentry) pwd
- 47. 51 Create parent fop iop i d “parent” memory storage d “child” 1. 查找 path & 建立 dentry
- 48. 52 Create parent fop iop i d “parent” memory storage d “child” 1. 查找 path & 建立 dentry 2. 執行 dir 自帶 create( )/mkdir( )/symlink( )/mknod( ) mknod( ) symlink( ) for link for dirmkdir( ) create( ) for file for char/block
- 49. 53 Create parent fop iop i d “parent” memory storage 1. 查找 path & 建立 dentry 2. 執行 dir 自帶 create( )/mkdir( )/symlink( )/mknod( ) a. 建立 inode, 安裝 ops mknod( ) symlink( ) for link for dirmkdir( ) create( ) for file for char/block fop iop i d “child”
- 50. 54 Create parent fop iop i d “parent” memory storage 1. 查找 path & 建立 dentry 2. 執行 dir 自帶 create( )/mkdir( )/symlink( )/mknod( ) a. 建立 inode, 安裝 ops b. 找地方放” target path”, if symlink mknod( ) symlink( ) for link for dirmkdir( ) create( ) for file for char/block fop iop i d “child”
- 51. 55 Create parent fop iop i d “parent” memory storage 1. 查找 path & 建立 dentry 2. 執行 dir 自帶 create( )/mkdir( )/symlink( )/mknod( ) a. 建立 inode, 安裝 ops b. 找地方放” target path”, if symlink c. 建立 dirent mknod( ) symlink( ) for link for dirmkdir( ) create( ) for file for char/block fop iop i d “child” child
- 52. 56 Create parent fop iop i d “parent” memory storage 1. 查找 path & 建立 dentry 2. 執行 dir 自帶 create( )/mkdir( )/symlink( )/mknod( ) a. 建立 inode, 安裝 ops b. 找地方 (e.g. page) 放” target path”, if symlink c. 建立 dirent d. 關聯 dentry/inode mknod( ) symlink( ) for link for dirmkdir( ) create( ) for file for char/block fop iop i d “child” child
- 53. 57 Delete parent fop iop i d “parent” child memory storage fop iop i d “child” 1. 查找 path
- 54. 58 Delete parent rmdir( ) fop iop i d “parent” child memory storage unlink( ) for file/link/char/block for dir fop iop i d “child” 1. 查找 path 2. 執行 parent inode 自帶 unlink( ) 或 rmdir( )
- 55. 59 Delete parent rmdir( ) fop iop i d “parent” memory storage unlink( ) for file/link/char/block for dir fop iop i d “child” 1. 查找 path 2. 執行 parent inode 自帶 unlink( ) 或 rmdir( ) a. 移除 dirent
- 56. 60 Delete parent rmdir( ) fop iop i d “parent” memory storage unlink( ) for file/link/char/block for dir fop iop i d “child” 1. 查找 path 2. 執行 parent inode 自帶 unlink( ) 或 rmdir( ) a. 移除 dirent b. inode nlink--
- 57. 61 Delete 1. 查找 path 2. 執行 parent inode 自帶 unlink( ) 或 rmdir( ) a. 移除 dirent b. inode nlink-- c. 移除 child dentry parent rmdir( ) fop iop i d “parent” memory storage unlink( ) for file/link/char/block for dir fop iop i
- 58. 68 File Open/Close file file file descriptor table task 1 file descriptor table task 2 file file i d i d i d i d file@vfs file file@task
- 59. 69 File Open/Close file file file descriptor table task 1 file descriptor table task 2 file file open: i d i d i d
- 60. 70 File Open/Close file file file descriptor table task 1 file descriptor table task 2 file file open: 1. 準備可用 fd(array index) i d i d i d
- 61. 71 File Open/Close file file file descriptor table task 1 file descriptor table task 2 file file open: 1. 準備可用 fd(array index) 2. 準備空 struct file file i d i d i d
- 62. 72 File Open/Close file file file descriptor table task 1 file descriptor table task 2 file file open: 1. 準備可用 fd(array index) 2. 準備空 struct file 3. 查找目標 (dentry/inode) file i d i d i d
- 63. 73 File Open/Close file file file descriptor table task 1 file descriptor table task 2 file file open: 1. 準備可用 fd(array index) 2. 準備空 struct file 3. 查找目標 (dentry/inode) 4. 建立 file 到 dentry/inode 關係 file i d i d i d
- 64. 74 File Open/Close file file file descriptor table task 1 file descriptor table task 2 file file open: 1. 準備可用 fd(array index) 2. 準備空 struct file 3. 查找目標 (dentry/inode) 4. 建立 file 到 dentry/inode 關係 5. 安裝 file 到 fd table file i d i d i d
- 65. 75 File Open/Close file file file descriptor table task 1 file descriptor table task 2 file file close: file i d i d i d
- 66. 76 File Open/Close file file file descriptor table task 1 file descriptor table task 2 file file close: 1. 歸還 fd file i d i d i d
- 67. 77 File Open/Close file file file descriptor table task 1 file descriptor table task 2 file file close: 1. 歸還 fd 2. 歸還 file( 移除 ) i d i d i d
- 68. 78 File Open/Close file file file descriptor table task 1 file descriptor table task 2 file file close: 1. 歸還 fd 2. 歸還 file( 移除 ) 3. 歸還 dentry/inode(count--) i d i d i d
- 69. 79 Read/Write fop iop address space p pp p p p p p file descriptor table file ino file ino read( ) aio_read( ) write( ) aio_write( ) userspace buffer storage write read