Re: [PATCH] nfs: Don't try mounting device as nfs root unless type fully matches

Sasha Levin
2012-03-31T15:22:21Z

ping? I saw that this one didn't get pulled into the tree.

On Mon, Jan 9, 2012 at 1:14 PM, Sasha Levin <levinsasha928@gmail.com> wrote:
> On Sat, 2012-01-07 at 13:12 -0500, Jim Rees wrote:
>> Chuck Lever wrote:
>>
>>   On Jan 7, 2012, at 4:12 AM, Sasha Levin wrote:
>>
>>   > Currently, we'll try mounting any device who's major device number is
>>   > UNNAMED_MAJOR as NFS root. This would happen for non-NFS devices as well (such
>>   > as 9p devices) but it wouldn't cause any issues since mounting the device
>>   > as NFS would fail quickly and the code proceeded to doing the proper mount:
>>   >
>>   >   [  101.522716] VFS: Unable to mount root fs via NFS, trying floppy.
>>   >   [  101.534499] VFS: Mounted root (9p filesystem) on device 0:18.
>>   >
>>   > Commit 6829a048 ("NFS: Retry mounting NFSROOT") has introduced retries when
>>   > mounting NFS root, which means that now we don't immediately fail and instead
>>   > it takes an additional 90+ seconds until we stop retrying.
>>   >
>>   > This meant that it would take an additional 90 seconds to boot when we're not
>>   > using a device type which gets detected in order before NFS.
>>
>>   The long timeouts are kind of irrelevant, in my view.  The real problem is
>>   that NFS was tried at all in this case.  That behavior was not introduced
>>   by 6829a058.
>>
>> The comment does imply that 6829a048 introduced a bug, but that's not true.
>> It uncovered a bug that was there before.
>>
>> I would change the part about "now we don't immediately fail."  It didn't
>> immediately fail before, but the timeout was short enough that you wouldn't
>> notice it.
>
> I tried to point out that 6829a048 changed the behavior which was
> described in the first paragraph, I didn't try to imply that 6829a048 is
> buggy on its own.
>
> I'm fine with changing the changelog to whatever will make it clearer.
>
> --
>
> Sasha.
>