Re: 1.2.9 lockup - more information

cloister bell (
Tue, 27 Jun 1995 20:03:08 -0700 (PDT)

> > > Kernel panic: EXT2-fs panic (device 22/1): ext2_find_entry: buffer head pointer is NULL
> > I had this error long time ago. After lot of hacking
> > I fond out that it was due to a directory that had
> > less size than a minimum (some number of blocks, I don't
> > remember). This error is not detected by e2fsck.
> >
> > Please, tell it Remi Card, the maintainer of ext2 fs.
> OK, I am cc'ing this to him now.
> I think corrupted filesystem shouldn't cause panic - maybe ext2_find_entry
> should just log this with printk and return NULL? From what I was looking
> at the code, this is a legitimate return value indicating an error.
> Or is this really such a serious problem that the system must panic, to
> avoid further damage? It would be nice to know this...

i would say that it is. recently i had an ext2fs problem (which may not
have been related to the ext2fs code itself) in which the root inode,
directory, and superblocks all got overwritten with garbage. had
ext2fsck plunged ahead and tried to fix things, it would almost certainly
have caused me to lose a *lot* of files. as it was, it was laborious but
possible to rebuild the missing parts and restore my filesystem without
the loss of anything irrecoverable. i'd really rather have the kernel
panic and stop rather than blindly trying to continue, possibly making
things worse.

what would have been *really* cool would have been for ext2fsck to have
detected this condition, and gone into some sort of interactive disk
editing mode in which it could have been fixed easier than with perl
scripts and lde.