[SOLVED]Illegal bitmap block(s) for home partition (ext4)

cupantae · 2011-10-16 15:39:32

Hi there,

Having shut down with halt yesterday, I booted up arch today. There, I was greeted with the dialogue that I have to run fsck manually. I can either log into a root shell or press Control-D to continue (reboot). Here is the output of fsck -y /dev/sda1 - The [...] parts indicate that the sequence is continued as such between the previous and next part. The output is really long:

fsck from util-linux-ng 2.17.2
e2fsck 1.41.14 (22-Dec-2010)
fsck.ext4: Group descriptors look bad... trying backup blocks...
One or more block group descriptor checksums are invalid.  Fix? yes

Group descriptor 0 checksum is invalid.  FIXED.
Group descriptor 1 checksum is invalid.  FIXED.
[...]
Group descriptor 127 checksum is invalid.  FIXED.
Block bitmap for group 128 is not in group.  (block 65569188)
Relocate? yes

Inode bitmap for group 128 is not in group.  (block 0)
Relocate? yes

Inode table for group 128 is not in group.  (block 1266791139)
WARNING: SEVERE DATA LOSS POSSIBLE.
Relocate? yes

Group descriptor 128 checksum is invalid.  FIXED.
Block bitmap for group 129 is not in group.  (block 524288)
Relocate? yes

Inode bitmap for group 129 is not in group.  (block 0)
Relocate? yes

Inode table for group 129 is not in group.  (block 62218)
WARNING: SEVERE DATA LOSS POSSIBLE.
Relocate? yes
[...]
Group descriptor 254 checksum is invalid.  FIXED.
Block bitmap for group 255 is not in group.  (block 0)
Relocate? yes

Inode bitmap for group 255 is not in group.  (block 0)
Relocate? yes

Inode table for group 255 is not in group.  (block 0)
WARNING: SEVERE DATA LOSS POSSIBLE.
Relocate? yes

Group descriptor 255 checksum is invalid.  FIXED.
Group descriptor 256 checksum is invalid.  FIXED.
[...]
Group descriptor 2980 checksum is invalid.  FIXED.
fsck.ext4: e2fsck_read_bitmaps: illegal bitmap block(s) for home

The full output can be viewed here: http://pastebin.com/K7XBXW48

Despite the friendly "FIXED"s, the problem persists. Running any variation of fsck I've tried yields exactly the same results. Checking on the web, what few discussions there were on the subject suggested copying the data and reformatting. I don't really want to do this because the partition is 400GB. I can access the data through a haiku install on a different partition so the data seems to be OK. Anyone know a way to repair these bitmap blocks?

The drive is a 3 year old Hitachi. I'm not ruling out the possibility that it is failing, but lets try assuming it isn't for the moment...

Thanks in advance,
Cupán Tae

Last edited by cupantae (2012-04-18 03:38:42)

R00KIE · 2011-10-16 15:50:50

The advice you found is good advice. If not for anything else you would have a backup.

I would not have enough confidence in that partition to keep storing important stuff there and for what it seems having fsck throw up a tantrum after an apparently clean shutdown requires further investigation, if nothing else to the hard disk integrity (it might really be dieing) or you may have bad ram, any of which would screw up with data on the disk and make use of that partition unreliable, unless you like unpredictable timebombs

cupantae · 2011-10-16 16:00:05

R00KIE wrote:

unless you like unpredictable timebombs

Unfortunately I don't. Or any timebombs masquerading as hard disks, for that matter.

I'll have a look around for backup media but for the time being, the partition is unformatted and any help is greatly appreciated.

CT

R00KIE · 2011-10-16 23:22:21

Tips:
- Don't write to the partition, writing may be ok or may break the rest (fits the timebomb description )
- Use memtest to give your ram a good shakeup, leave it running overnight (after you have seen it run for a couple hours just to make sure nothing gets too hot specially if you are using a laptop)
- Use smartctl (from smartmontools) to check your disk status, start with 'smartctl -A /dev/sd?' and see if there are any reallocated sectors (backup your stuff, double quick, preferably don't use the disk until you have a backup media), current pending sectors or offline uncorrectable (indicate something went wrong but doesn't mean the disk is about to die).
- Check the output of dmesg and look for any errors related to the HD, it is another sign that something is not right.
- Check the cabling, something might have gotten loose.

Can't remember anything else for now. After you backup all your stuff you can give the hard disk a good shakeup with badblocks.

cupantae · 2011-10-18 23:05:25

Well, here I am back in Arch; finally getting round to writing up a summary. I know most Arch users don't need this kind of hand-holding, but there are a few posts like this on the web, none of them suggesting that the hardware might be OK.

TL;DR: The drive is NOT necessarily malfunctioning, but you will have to back up your data, delete the partition, recreate it and transfer back.

This is an account of what I did that was useful, so that it functions as a HOWTO to others in the same situation:

Look on your hard disk manufacturer's website for their disk diagnostics tool. Hitachi have one, I can't say for any other manufacturers, of course.
If it reports an error, look for your warrantee and ignore step 6; otherwise continue.
Put SystemRescueCD on to a usb stick as per their directions. (Or your favourite restore system on your favourite medium )
Get backup media. Preferably larger than the partition to be restored.
Boot SRCD up. Use TestDisk to copy what you need into the backup media.
- Note 1: Red files are those that had been deleted.
- Note 2: TestDisk preserves the directories right down to / so always copy to the same point on the backup media!
Use (g)parted to delete the bad partition and then to recreate it. Copy in the backed up data.

Thanks a million, R00KIE. I suppose I followed the spirit of your advice

Arch Linux

#1 2011-10-16 15:39:32

[SOLVED]Illegal bitmap block(s) for home partition (ext4)

#2 2011-10-16 15:50:50

Re: [SOLVED]Illegal bitmap block(s) for home partition (ext4)

#3 2011-10-16 16:00:05

Re: [SOLVED]Illegal bitmap block(s) for home partition (ext4)

#4 2011-10-16 23:22:21

Re: [SOLVED]Illegal bitmap block(s) for home partition (ext4)

#5 2011-10-18 23:05:25

Re: [SOLVED]Illegal bitmap block(s) for home partition (ext4)

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