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From: bert hubert <ahu@ds9a.nl>
To: Shesha Sreenivasamurthy <shesha@inostor.com>
Cc: "'linux-kernel@vger.kernel.org'" <linux-kernel@vger.kernel.org>,
	"'kernelnewbies@nl.linux.org'" <kernelnewbies@nl.linux.org>
Subject: Re: O_DIRECT
Date: Tue, 20 Jul 2004 20:48:24 +0200	[thread overview]
Message-ID: <20040720184824.GA30090@outpost.ds9a.nl> (raw)
In-Reply-To: <40FD561D.1010404@inostor.com>

On Tue, Jul 20, 2004 at 10:27:57AM -0700, Shesha Sreenivasamurthy wrote:
> I am having trouble with O_DIRECT. Trying to read or write from a block 
> device partition.
> 
> 1. Can O_DIRECT be used on a plain block device partition say 
> "/dev/sda11" without having a filesystem on it.

As fas as I know, yes, but be aware that O_DIRECT requires page aligned
addresses! (an integral of 4096 on most systems).

> 2. If no file system is created then what should be the softblock size. 
> I am using the IOCTL "BLKBSZGET". Is this correct?

No idea what you mean - but see above about the aligned addresses.

> 3. Can we use SEEK_END with O_DIRECT on a partition without filesystem.

I see no reason why not. Good luck!

-- 
http://www.PowerDNS.com      Open source, database driven DNS Software 
http://lartc.org           Linux Advanced Routing & Traffic Control HOWTO

  reply	other threads:[~2004-07-20 18:55 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-07-20 17:27 O_DIRECT Shesha Sreenivasamurthy
2004-07-20 18:48 ` bert hubert [this message]
     [not found]   ` <40FD6FCB.5020408@inostor.com>
2004-07-20 20:17     ` O_DIRECT bert hubert
2004-07-21  0:10   ` O_DIRECT Rob van Nieuwkerk
2004-07-21 14:45   ` O_DIRECT Devel
     [not found]     ` <40FE9F3F.2090205@inostor.com>
2004-07-22  9:46       ` O_DIRECT Devel
2004-07-24  9:56   ` O_DIRECT Rogier Wolff
2004-07-26  1:24     ` O_DIRECT Andrew Morton
2004-07-21  0:05 ` O_DIRECT Rob van Nieuwkerk
     [not found]   ` <40FEA382.8050700@inostor.com>
2004-07-21 17:20     ` O_DIRECT Rob van Nieuwkerk
     [not found]       ` <40FEAF70.4070407@inostor.com>
2004-07-21 18:15         ` O_DIRECT Rob van Nieuwkerk
2004-07-21 18:45           ` O_DIRECT Shesha Sreenivasamurthy
2004-07-21 23:18           ` O_DIRECT Shesha Sreenivasamurthy
2004-07-21 23:54             ` O_DIRECT Rob van Nieuwkerk
2004-07-22  0:00               ` O_DIRECT Shesha Sreenivasamurthy
2004-07-22  0:18                 ` O_DIRECT Rob van Nieuwkerk
2004-07-22  0:48                   ` O_DIRECT Shesha Sreenivasamurthy
  -- strict thread matches above, loose matches on Subject: below --
2004-12-02  2:50 O_DIRECT Lever, Charles
2004-12-02  1:01 O_DIRECT Steve French
     [not found] <200306262021.h5QKLhN10771@devserv.devel.redhat.com>
     [not found] ` <1056706819.2418.11.camel@sisko.scot.redhat.com>
2003-06-27 10:35   ` O_DIRECT Stephen C. Tweedie
2003-06-27 11:07     ` O_DIRECT Alan Cox
     [not found] <200208291113.g7TBDut26852@tench.street-vision.com>
2002-08-29 11:22 ` O_DIRECT Peter T. Breuer
2002-08-29 12:14 ` O_DIRECT Peter T. Breuer
2002-08-29 11:04 O_DIRECT Peter T. Breuer
2001-04-12 21:09 O_DIRECT Andrea Arcangeli

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