Re: latest -git: A peculiar case of a stuck process (ext3/sched-related?)

From: Vegard Nossum
Date: Fri Jul 18 2008 - 06:39:34 EST


On Fri, Jul 18, 2008 at 12:32 PM, Andrew Morton
<akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
> On Fri, 18 Jul 2008 12:17:17 +0200 "Vegard Nossum" <vegard.nossum@xxxxxxxxx> wrote:
>
>> And the ext3_find_entry() corresponds to this line:
>>
>> for (; de < top; de = ext3_next_entry(de)) /* <--- HERE! */
>> if (ext3_match (namelen, name, de)) {
>> if (!ext3_check_dir_entry("ext3_find_entry",
>> dir, de, bh,
>> (block<<EXT3_BLOCK_SIZE_BITS(sb))
>> +((char *)de - bh->b_data))) {
>> brelse (bh);
>> *err = ERR_BAD_DX_DIR;
>> goto errout;
>> }
>> *res_dir = de;
>> dx_release (frames);
>> return bh;
>> }
>>
>> Is it possible that this loop can get stuck with a corrupt filesystem image?
>
> yup. ext2 did that a couple of times. See the explicit check for
> de->rec_len == 0 in ext2_find_entry().
>
> We fixed one filesystem and forgot the others. Again.

Wow, that change is OLD, though:

commit aa4f3f285643956bb614cf7b8f88e15f3a375886
Author: Andrew Morton <akpm@xxxxxxxxxx>
Date: Mon Apr 29 23:51:34 2002 -0700

[PATCH] ext2 directory handling

Will you also send the patch for ext3? :-)


Vegard

--
"The animistic metaphor of the bug that maliciously sneaked in while
the programmer was not looking is intellectually dishonest as it
disguises that the error is the programmer's own creation."
-- E. W. Dijkstra, EWD1036
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