Re: UBIFS assert failed in ubifs_dirty_inode

Artem Bityutskiy
2010-01-27T04:20:29Z

On Tue, 2010-01-26 at 22:07 -0500, Jeff Angielski wrote:
> Matt Mackall wrote:
> > On Tue, 2010-01-26 at 20:44 -0500, Jeff Angielski wrote:
> >> Artem Bityutskiy wrote:
> >>> On Mon, 2010-01-25 at 23:48 -0600, Matt Mackall wrote:
> >>>> Hmm. I'd just as soon drop it entirely. Here's a patch. Herbert, you
> >>>> want to send this through your crypto tree?
> >>>>
> >>>>
> >>>> random: drop weird m_time/a_time manipulation
> >>>>
> >>>> No other driver does anything remotely like this that I know of except
> >>>> for the tty drivers, and I can't see any reason for random/urandom to do
> >>>> it. In fact, it's a (trivial, harmless) timing information leak. And
> >>>> obviously, it generates power- and flash-cycle wasting I/O, especially
> >>>> if combined with something like hwrngd. Also, it breaks ubifs's
> >>>> expectations.
> >>>>
> >>>> Signed-off-by: Matt Mackall <mpm@selenic.com>
> >>>>
> >>>> diff -r 29db0c391ce8 drivers/char/random.c
> >>>> --- a/drivers/char/random.c Sun Jan 17 11:01:16 2010 -0800
> >>>> +++ b/drivers/char/random.c Mon Jan 25 23:32:00 2010 -0600
> >>>> @@ -1051,12 +1051,6 @@
> >>>> /* like a named pipe */
> >>>> }
> >>>>
> >>>> - /*
> >>>> - * If we gave the user some bytes, update the access time.
> >>>> - */
> >>>> - if (count)
> >>>> - file_accessed(file);
> >>>> -
> >>>> return (count ? count : retval);
> >>>> }
> >>>>
> >>>> @@ -1116,8 +1110,6 @@
> >>>> if (ret)
> >>>> return ret;
> >>>>
> >>>> - inode->i_mtime = current_fs_time(inode->i_sb);
> >>>> - mark_inode_dirty(inode);
> >>>> return (ssize_t)count;
> >>>> }
> >>> It may brake other FSes expectations, theoretically, as well.
> >>>
> >>> Anyway, I'm perfectly fine if this is removed.
> >>>
> >>> Jeff, could you please try Matt's patch and report back if you still
> >>> have issues or not. If no, you can use this as a temporary work-around
> >>> until a proper fix hits upstream or ubifs-2.6.git.
> >> Matt's patch did not compile as written. I tried to implement what I
> >> think he was trying to do and created this patch (it seems to match the
> >> guts of what inode_setattr() was looking for):
> >>
> >>
> >> diff --git a/drivers/char/random.c b/drivers/char/random.c
> >> index 8258982..70f16c7 100644
> >> --- a/drivers/char/random.c
> >> +++ b/drivers/char/random.c
> >> @@ -1108,6 +1108,7 @@ static ssize_t random_write(struct file *file,
> >> const char __user *buffer,
> >> {
> >> size_t ret;
> >> struct inode *inode = file->f_path.dentry->d_inode;
> >> + struct iattr attr;
> >>
> >> ret = write_pool(&blocking_pool, buffer, count);
> >> if (ret)
> >> @@ -1116,8 +1117,12 @@ static ssize_t random_write(struct file *file,
> >> const char __user *buffer,
> >> if (ret)
> >> return ret;
> >>
> >> - inode->i_mtime = current_fs_time(inode->i_sb);
> >> - mark_inode_dirty(inode);
> >> + attr.ia_mtime = current_fs_time(inode->i_sb);
> >> + attr.ia_valid = ATTR_MTIME;
> >> + ret = inode_setattr(inode, &attr);
> >> + if (ret)
> >> + return ret;
> >> +
> >> return (ssize_t)count;
> >> }
> >>
> >> However, this patch does not fix the problem. I still see the same
> >> errors. Matt, is this what you were trying to do?
> >
> > That doesn't look anything like my patch? And mine was test compiled.
>
> Ahh, you would be right. I mixed up authors. My bad. ;)
>
> Matt's patch that removes the offending code works fine.
>
> Artem's patch that tries to fix the offending code (and does not compile
> as posted) does not work.

Thanks for testing. So, who would bring Matt's patch upstream then, hmm?

--
Best Regards,
Artem Bityutskiy (Артём Битюцкий)