On Mon, Jan 13, 2025 at 11:33:45AM -0500, Theodore Ts'o wrote:
> On Mon, Jan 13, 2025 at 12:49:19AM -0500, Catalin Patulea wrote:
> >
> > I have an ext3 filesystem on which I manually enabled huge_file
> > (files >2 TB) using tune2fs; then created a 3 TB file (backup image
> > of another disk). Now, I am running e2fsck and it reports errors:
>
> Hmm, it looks like this has been broken for a while. I've done a
> quick look, and it appears this has been the case since e2fsprogs
> 1.28 and this commit:
>
> commit da307041e75bdf3b24c1eb43132a4f9d8a1b3844
> Author: Theodore Ts'o <tytso@xxxxxxx>
> Date: Tue May 21 21:19:14 2002 -0400
>
> Check for inodes which are too big (either too many blocks, or
> would cause i_size to be too big), and offer to truncate the inode.
> Remove old bogus i_size checks.
>
> Add test case which tests e2fsck's handling of large sparse files.
> Older e2fsck with the old(er) bogus i_size checks didn't handle
> this correctly.
>
> I think no one noticed since trying to support files this large on a
> non-extent file is so inefficient and painful that in practice anyone
> trying to use files this large would be using ext4, and not a really
> ancient ext3 file system.
>
> The fix might be as simple as this, but I haven't had a chance to test
> it and do appropriate regression tests....
>
> diff --git a/e2fsck/pass1.c b/e2fsck/pass1.c
> index eb73922d3..e460a75f4 100644
> --- a/e2fsck/pass1.c
> +++ b/e2fsck/pass1.c
> @@ -3842,7 +3842,7 @@ static int process_block(ext2_filsys fs,
> problem = PR_1_TOOBIG_DIR;
> if (p->is_dir && p->num_blocks + 1 >= p->max_blocks)
> problem = PR_1_TOOBIG_DIR;
> - if (p->is_reg && p->num_blocks + 1 >= p->max_blocks)
> + if (p->is_reg && p->num_blocks + 1 >= 1U << 31)
Hmm -- num_blocks is ... the number of "extent records", right? And on
a !extents file, each block mapped by an {in,}direct block counts as a
separate "extent record", right?
In that case, I think (1U<<31) isn't quite right, because the very large
file could have an ACL block, or (shudder) a "hurd translator block".
So that's (1U<<31) + 2 for !extents files.
For extents files, shouldn't this be (1U<<48) + 2? Since you /could/
create a horrifingly large extent tree with a hojillion little
fragments, right? Even if it took a million years to create such a
monster? :)
--D
> problem = PR_1_TOOBIG_REG;
> if (!p->is_dir && !p->is_reg && blockcnt > 0)
> problem = PR_1_TOOBIG_SYMLINK;
>
>
> - Ted
>
