The LKL-based Haiku driver has progressed well in the last few weeks.
The set of features already implemented:
mounting and unmounting ext3, ext4 disk images*, both read-only and read-write listing file system attributes (read-only/read-write, file system size, number of files created, number of files remaining to be created, etc.) browsing the contents of any folder on the file system listing file permissions, owner, group, type (directory, symlink, regular file, etc.
Porting LKL to Haiku's kernel API may not have been very hard, but convincing Haiku to load a properly built LKL-based add-on has presented some interesting and challenging problems.
The first milestone in this GSoC journey to building a generic file system driver based on Linux kernel code is booting LKL (Linux Kernel Library) inside Haiku.
For the short attention span: it works :)
...
KERN: KDiskDeviceManager::_AddDiskSystem() done: No error
KERN: file system: file_systems/iso9660/v1
KERN: KDiskDeviceManager::_AddDiskSystem(file_systems/iso9660/v1)
KERN: KDiskDeviceManager::_AddDiskSystem() done: No error
KERN: lklhaikufs: unhandled pheader type 0x4
KERN: file system: file_systems/lklhaikufs/v1
KERN: KDiskDeviceManager::_AddDiskSystem(file_systems/lklhaikufs/v1)
KERN: khaiku_env_timer:: LKL_TIMER_INIT
KERN: [lkl-console] Linux version 2.6.29 (gringo@lethe) (gcc version 4.4.4 (GCC) ) #10 Fri Jun 18 14:45:38 EEST 2010
KERN: [lkl-console] Built 1 zonelists in Zone order, mobility grouping on. Total pages: 16256
KERN: [lkl-console] Kernel command line:
KERN: [lkl-console] lkl: IRQs initialized
KERN: [lkl-console] PID hash table entries: 256 (order: 8, 1024 bytes)
KERN: [lkl-console] lkl: timer initialized
KERN: [lkl-console] Dentry cache hash table entries: 8192 (order: 3, 32768 bytes)
KERN: [lkl-console] Inode-cache hash table entries: 4096 (order: 2, 16384 bytes)
KERN: [lkl-console] Memory available: 64900k/65536k RAM, (862k kernel code, 270k data)
KERN: [lkl-console] Mount-cache hash table entries: 512
KERN: [lkl-console] bio: create slab at 0
KERN: [lkl-console] io scheduler noop registered (default)
KERN: [lkl-console] lkl: syscall interface initialized
KERN: [lkl-console] console [lkl_console0] enabled
KERN: [lkl-console] Warning: unable to open an initial console.
KERN: [lkl-console] Switched to NOHz mode on CPU #0
KERN: [lkl-console] System halted.
KERN: khaiku_env_timer:: LKL_TIMER_SHUTDOWN
KERN: [lkl-console] lkl: IRQs freed
KERN: lkl: halt user callback called
KERN: KDiskDeviceManager::_AddDiskSystem() done: No error
KERN: file system: file_systems/nfs/v1
KERN: KDiskDeviceManager::_AddDiskSystem(file_systems/nfs/v1)
...
These are messages from
/var/log/syslog that are generated when Haiku searches for available file system add-ons. One of those drivers is my
lklhaikufs driver. Messages with
[lkl-console] are from LKL (similar to what you see when a normal Linux kernel boots) :)
Haiku has great support for its own file system, but most others are only available read-only or not accessible. Providing reliable read-write support to one such file system is a complex task, and needs to be repeated for each type of file system.
Linux contains state of the art, full featured implementations for a large number of file systems.
lkl-haiku-fsd is a generic driver based on the Linux kernel library (LKL), reusing Linux' optimized and debugged file system implementations.
