On Sep 25, 2002 15:44 -0400, Theodore Ts'o wrote:
> On Tue, Sep 24, 2002 at 09:07:03PM +0200, Jure Pecar wrote:
> > Can you #define 'quite safe' ? :)
> >
> > Like, is there a possibility of corrupting existing data? Is it production
> > ready?
> > >From all the new filesystems that came out recently i only really trust ext3
> > ... but i really need some form of indexing (large mail spools, maildir).
>
> I've done a lot of testing on it, and so I believe it's ready for 2.5,
> and will be running it on my laptop. (This last says a lot; I didn't
> trust 2.4 for a very long time on my laptop....)
>
> That being said, I'd probably give it a bit more shakedown testing
> before I could in good conscience recommend it on a production mail
> server. But that's my natural conservatism; other people are more
> adventurous.
One known problem - don't use it with NFS on top - it will overflow the
stack in do_split (it may even overflow without NFS, but in the presence
of interrupts or something). A sub-optimal fix is below (the "optimal"
fix is not yet working, but avoids the allocation and the potential
panic ;-). The diff is only approximately a real diff, but you can get
the general idea (it may even apply, I don't know).
Cheers, Andreas
=======================================================================
--- linux/fs/ext3/namei.c.orig 25 Jul 2002 21:35:21 -0000 1.10
+++ linux/fs/ext3/namei.c 23 Sep 2002 23:44:13 -0000 1.12
@@ -778,7 +778,7 @@
u32 newblock;
unsigned MAX_DX_MAP = PAGE_CACHE_SIZE/EXT3_DIR_REC_LEN(1) + 1;
u32 hash2;
- struct dx_map_entry map[MAX_DX_MAP];
+ struct dx_map_entry *map;
char *data1 = (*bh)->b_data, *data2, *data3;
unsigned split;
ext3_dirent *de, *de2;
@@ -798,6 +798,9 @@
data2 = bh2->b_data;
+ map = kmalloc(sizeof(*map) * MAX_DX_MAP, GFP_KERNEL);
+ if (!map)
+ panic("no memory for do_split\n");
count = dx_make_map ((ext3_dirent *) data1, blocksize, map);
split = count/2; // need to adjust to actual middle
dx_sort_map (map, count);
@@ -828,6 +831,7 @@
brelse (bh2);
ext3_journal_dirty_metadata (handle, frame->bh);
dxtrace(dx_show_index ("frame", frame->entries));
+ kfree(map);
return de;
}
#endif
--
Andreas Dilger
http://www-mddsp.enel.ucalgary.ca/People/adilger/
http://sourceforge.net/projects/ext2resize/
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