From: Theodore Ts'o <tytso@mit.edu>
To: David Turner <novalis@novalis.org>
Cc: Andreas Dilger <adilger@dilger.ca>, linux-ext4@vger.kernel.org
Subject: Re: [PATCH] e2fsck: Correct ext4 dates generated by old kernels
Date: Wed, 25 Nov 2015 04:46:32 -0500 [thread overview]
Message-ID: <20151125094632.GA2632@thunk.org> (raw)
In-Reply-To: <1448431295.7696.9.camel@novalis.org>
On Wed, Nov 25, 2015 at 01:01:35AM -0500, David Turner wrote:
> On Tue, 2015-11-24 at 14:34 -0700, Andreas Dilger wrote:
> > +static int check_inode_extra_negative_epoch(__u32 xtime, __u32
> > extra) {
> > + return (xtime & (1 << 31)) != 0 &&
>
> On a re-read, I think the bitshift is technically undefined behavior
> because 1 is signed and 2**31 is not representable as a signed (32-bit)
> int. Changing it to 1U should fix it.
Instead of doing all of the bitshifts, I was thinking about doing
something much simpler:
...
if (inode->ctime_hi == 3 && fix_problem(....)
inode->ctime_hi = 0;
if (inode->mtime_hi == 3 && fix_problem(....)
inode->mtime_hi = 0;
Hmm? That should work just as well, and is easier to read and
understand what's going on, and matches with the test we are using in
the kernel.
- Ted
next prev parent reply other threads:[~2015-11-25 9:46 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-24 21:34 [PATCH] e2fsck: Correct ext4 dates generated by old kernels Andreas Dilger
2015-11-24 21:37 ` Andreas Dilger
2015-11-25 6:01 ` David Turner
2015-11-25 9:46 ` Theodore Ts'o [this message]
2015-11-26 5:27 ` David Turner
-- strict thread matches above, loose matches on Subject: below --
2016-02-18 19:57 Andreas Dilger
2016-03-07 3:43 ` Theodore Ts'o
2016-03-07 11:34 ` Andreas Dilger
2016-03-07 15:27 ` Theodore Ts'o
2016-03-09 8:57 ` David Turner
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