Ext2-fs panic

Jason Burrell (jburrell@crl.com)
Tue, 10 Sep 1996 20:58:57 -0500 (CDT)


I have two IDE drives on this old 386 here, and each drive has a swap
partition. After realizing that all my programs were running on /dev/hdb,
and my swap was being used first on /dev/hda, I decided to unmount and
remount the partitions, changing the priorities to favour /dev/hdb. (I
assume the switching overhead costs more than the movement, especially
considering that something here, presumably the drive, eats a lot of
"system" time as shown in 'top'.)

Anyway, I fatfingered my remounting of the swap partition on /dev/hdb, and
entered /dev/hdb3 rather than /dev/hdb4. /dev/hdb3 is my /usr partition, and
was already mounted. 'swapon' complained, of course, saying "hbd3: invalid
argument," and aborted. I mounted /dev/hdb4 as swap, and was promptly hit
with this:

Ext2-fs panic (device 03:43):read_inode_bitmap: cannot read inode bitmap.
block_group=108, inode_bitmap=884744.

No entry in the log, nothing. I also had similar problems with kernel panics
when I changed the partitioning on my drives, altering some ext2 partitions,
and rebooting to reload the partition table before running mke2fs, and
forgot to remove the partitions from the /etc/fstab file. In that situation,
it claims to try to read beyond the end of the device. I had to get a
bootdisk, mount the root fs, and hack up /etc/fstab manually.

I understand the second error ("attempt to read beyond end of device"), but
I'm curious as to why this is an offence punishable by panic. The first
error, though, is something that should not happen.

Normally, I'd go in, try to "fix" the problem, and then send out a patch.
I'm not doing so because this machine is incredibly slow (5-7 hours for a
kernel compile), and I'm not sure if this is an intended behavior.