Date: Wed, 23 Oct 2002 14:36:46 -0400 (EDT) From: John Baldwin <jhb@FreeBSD.org> To: Terry Lambert <tlambert2@mindspring.com> Cc: current@FreeBSD.ORG, Vitaly Markitantov <vm@dics.com.ua>, Sheldon Hearn <sheldonh@starjuice.net> Subject: Re: smbfs broken? Message-ID: <XFMail.20021023143646.jhb@FreeBSD.org> In-Reply-To: <3DB6EB16.2025AAE3@mindspring.com>
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On 23-Oct-2002 Terry Lambert wrote:
> Sheldon Hearn wrote:
>> [client]
>> $ for i in `jot 512 7680`; do
>> cp /smb/urchin/pub/bytes/$i . || break;
>> done
>> cp: ./8145: Bad address
>>
>> If I truss the cp process, I get this:
>>
>> [...]
>> open("/smb/urchin/pub/bytes/8145",0x0,00) = 3 (0x3)
>> open("./8145",0x401,00) = 4 (0x4)
>> mmap(0x0,8145,0x1,0x1,3,0x0) = 671461376 (0x2805b000)
>>
>> I don't have my laptop set up as a serial debugging client now, so
>> that's as far as I can go. :-(
>
> AHA!
>
> The reason an FFS write resulted in an SMBFS read is that
> you had mmap()'ed an SMBFS file, and then wrote a mapped
> but-not-in-core page to the target FFS file.
>
> Knowing that the code involved is in the paging path of the
> SMBFS code is important.
>
> What happens if you:
>
> dd if=/smb/urchin/pub/bytes/8145 of=8145
>
> ? I expect that it works, no problem.
>
> This localizes the problem to the VOP_GETPAGES that gets hit
> in the SMBFS case.
Umm, terry. Did you even read all of this thread? He did a
simple cat(1) later which used read(2) and it got an actual
error back from read(2). Also, Sheldon is not the original
submitter of the problem report.
--
John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve!" - http://www.FreeBSD.org/
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