On Monday 28 January 2008 06:33, Andrew Morton wrote:

On Sun, 27 Jan 2008 03:17:09 +0100 (CET) Andi Kleen [off-list ref] wrote:

quoted

I checked ext3_ioctl and it looked largely safe to not be used
without BKL.  So convert it over to unlocked_ioctl.

The only case where I wasn't quite sure was for the
dynamic fs grow ioctls versus umounting -- I kept the BKL for those.

Please cpoy linux-ext4 on ext2/3/4 material.

Ok I'll resubmit those to tytso/ext4-devel (or perhaps he has already seen 
them) 

I skippped a lot of these patches because I just got bored of fixing
rejects.  Now is a very optimistic time to be raising patches against
mainline.

JFS and CIFS are already taken care of by the maintainers. This leaves
remote_llseek which touches a couple of file systems. Could you
perhaps take that one only please? And perhaps Nick's minix 
patchkit which looks safe to me and is unlikely to cause conflicts.

quoted

+		/* AK: not sure the BKL is needed, but this might prevent
+		 * races against umount */
+		lock_kernel();
 		err = ext3_group_add(sb, &input);
 		journal_lock_updates(EXT3_SB(sb)->s_journal);
 		journal_flush(EXT3_SB(sb)->s_journal);
 		journal_unlock_updates(EXT3_SB(sb)->s_journal);
+		unlock_kernel();

The ext3_ioctl() caller has an open fd against the fs - should be
sufficient to keep unmount away?

True. I am still conservative because group_add is a lot of code
which I didn't fully check. But with the open fd it's likely safe
to not take the BKL because there is nothing else (except
readdir?) in ext* that takes it.

It's all reached the stage of stupid.

I'll resubmit ->fasync_unlocked against -mm.

Also I wanted to recheck the ->f_flags locking. I found one bug in those 
already and I can extract the bug fix for that one. 

-Andi