OpenFirmware ext4 filesystem support

[FGrose]

observed on XO-1.75 B1 with q4b07 and q4b08 with os1, os40, & os41

at OFW command line:

fs-update ext:\os41.zd

returns

ext:\os41.zd:1: O┴ ?
 
WARNING: The file said highest block 0 but wrote only as high as block 0
00:00:00
ok

The same os41.zd file copied to an SD card formatted as vfat did not fail.

[FGrose]

logs

[Quozl]

OpenFirmware does not have ext4 support, so I wouldn't expect this to work.

Please provide the size in blocks of the external SD card, as shown by /proc/partitions, and the command used to format the card under Linux.

Meanwhile, use ext2, ext3, or fat.

[FGrose]

Replying to Quozl:

Please provide the size in blocks of the external SD card, as shown by /proc/partitions, and the command used to format the card under Linux.

device 3979776 blocks
partition 3978240 blocks

The device was probably formatted with the Fedora Disk Utility. It reports,
Master Boot Record partitioning
Partition Type: Linux (0x83)
Type: Ext4 (version 1.0)

tune2fs -l output attached

[Quozl]

Reproduced.

Excluded fs-update. Excluded external SD port.

---

A text file and a .zd file were placed on ext4 formatted external SD card, and on an ext4 formatted USB drive, and OpenFirmware was used to read them into a 0xff filled buffer. The .zd file contained this byte sequence as first line: "zblocks: 20000 7331", hex:

7a 62 6c 6f 63 6b 73 3a 20 32 30 30 30 30 20 37 33 33 31 0a

The buffer contained this byte sequence after read:

7a 14 58 96 fa 75 0b 72 7a 1c ee 3a 73 1a 40 dc 71 d4 b0 a4

Displaying the text file with more showed no useful output.

[wmb@…]

svn 2798 adds the ability to read from an ext4 filesystem.

svn 2799 adds the ability to delete files from ext4.

General file writing is not yet implemented.

[Quozl]

Read and delete capability released in Q4C12.

[wmb@…]

svn 2815 corrects a problem with group descriptor checksum management for ext4. The impact of that problem is filesystem corruption (correctable by fsck) when you delete a file on an ext4 filesystem with OFW.

Another problem has cropped up. If the journal is dirty (from Linux), OFW fails to recover it correctly.

[wmb@…]

The aforementioned problem with journal recovery is fixed by svn 2816.

[wmb@…]

svn 2817 fixes another journal recovery problem and enables creating new files and writing to them on ext4 filesystems. The writing works by using the old block-mapped format, which can coexist with the new extent-mapped format

[Quozl]

Q4D01 released, please test.

[FGrose]

Tested with os30.zd4 on an ext4 formatted USB flash drive.

fs-update worked.