Questions:
- How can I find 'find last used block + 1' on a reiser4 partition and truncate it so I can use spare space for another partition type . ?


Any tools or commands to do/find this ?
Thanks
--Glenn


blocks: 488378640
free blocks: 217146980
file count: 188313

##

using opensuse and Reiser4 enabled kernel
partition details and followig shows:

# fdisk -l
Disk /dev/sdb: 2000.4 GB, 2000398934016 bytes, 3907029168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes

# mount /dev/sdb /media/disk

# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sdb 1.8T 747G 1.0T 43% /media/disk

# umount /dev/sdb


# fsck.reiser4 --check /dev/sdb
*******************************************************************
This is an EXPERIMENTAL version of fsck.reiser4. Read README first.
*******************************************************************

Fscking the /dev/sdb block device.


Will check the consistency of the Reiser4 SuperBlock.


Will check the consistency of the Reiser4 FileSystem.


Continue?


(Yes/No): yes
***** fsck.reiser4 started at Tue Feb 24 17:03:22 2015
Reiser4 fs was detected on /dev/sdb.


Master super block (16):
magic: ReIsEr4
blksize: 4096
format: 0x0 (format40)
uuid: 3006ced1-7490-4ea8-a9b8-d82143c6bede
label: <none>

Format super block (17):
plugin: format40
description: Disk-format plugin.
version: 0
magic: ReIsEr40FoRmAt
mkfs id: 0x1ddaf754
flushes: 0
blocks: 488378640
free blocks: 217146980
root block: 37017218
tail policy: 0x2 (smart)
next oid: 0xedade
file count: 188313
tree height: 6
key policy: LARGE

I have not used reiserfs in some time but resize_reiserfs should be able to shrink the filesystem. Since your drive is not partition that should be the only step required.

Make sure you have a good backup just in case...

Just how do you plan to have "another partition type" on a drive that is not partitioned?

Good point. I feel stupid...

I think all of us have made posts here that overlooked something fundamental.

Anyone who takes on the task of moderating this mass of postings has my deepest respect.

Hello,

Answer to Question "Just how do you plan to have "another partition type" on a drive that is not partitioned?"

My thinking

So disk may have:

###.#..#..##.........

# = used blocks
. = free blocks

# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sdb 1.8T 747G 1.0T 43% /media/disk

unmounted [/dev/sdb]
# fdisk -l /dev/sdb

Disk /dev/sdb: 2000.4 GB, 2000398934016 bytes, 3907029168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes

step 1. Shrink Reiser4 partition.
[I need tools to shrink Reiser4 volume but cannot find any]
need to find block number of 'last used block + 1'


- Disk I think has a quantity of free space at the end of the Reiser 4 partition

step2.
I need some tools to find block number of 'last used block + 1'

[need tools/commands to shrink Reiser4 volume but cannot find any]

create reiser3 [reiserfs] partition in spare space after last block used of [reiser4] partition.

resize_reiserfs cant shrink Reiser4 partition - I tried.
[error as follows]

# resize_reiserfs -s -1G /dev/sdb
resize_reiserfs 3.6.24

cannot open '/dev/sdb': Unknown error 2127439231
#

Anyone know of tools to shrink Reiser4 partition


Details about volume and space used
-----------------------------------

blocks: 488378640
free blocks: 217146980
file count: 188313


Thanks for your help
--Glenn

You need to think about what has been said to you.
You cannot simply add a partition to this device. Period.

You (presumably) chose to use the entire (unpartitioned) device for your data. You cannot change that without reformatting the device. Back up your data and do as you must. FWIW I too gave up on reiser many years ago.

Surely if OP were to find a way of resizing and compacting his reiser4 filesystem, he could then reduce the partition size and create a new partition in the remaining disk space? Or are you saying that reiser4 doesn't support such resizing and compacting?

Nothing to do with the filesystem - there is no partition table.

Ah, thanks. I've only ever dealt with partitioned disks. I didn't realise that you couldn't partition a non-partitioned disk after the fact.

The MBR is not protected or reserved space nor is there a requirement you have to have one. If the OP creates one after the fact the existing data will be lost.

Would creating a LVM partition based on the underlying raw disk and then using lvreduce (after, somehow, compacting the reiser4 filesystem) work?

The runs into the same problem as adding a partition table. The LVM PV header would be placed at the beginning of the disk, overwriting the start of the existing reiserfs filesystem.

The free space in the existing filesystem is currently less than 50% of the disk (blocks: 488378640, free blocks: 217146980). There simply isn't enough room to make a new copy of the data elsewhere on that same disk, and I don't know of any existing tool that supports an overlapping move of a filesystem. Yes, it's possible in concept to cobble together something using dmsetup mappings to shift a filesystem in sections, but that's going to be a lot more work, and a lot more dangerous, than just saving the data somewhere else and reformatting the disk.

And, if you don't have "somewhere else" to save the data, then your data is apparently not important enough to you to be worth having a backup, so why worry about it?