Date: Thu, 19 Jul 2007 11:39:10 -0500 From: Josh Paetzel <josh@tcbug.org> To: "M. Warner Losh" <imp@bsdimp.com> Cc: LoN_Kamikaze@gmx.de, koitsu@freebsd.org, freebsd-stable@freebsd.org, idiotbg@gmail.com Subject: Re: removing external usb hdd without unmounting causes reboot? Message-ID: <200707191139.14063.josh@tcbug.org> In-Reply-To: <20070719.084821.-202614780.imp@bsdimp.com> References: <200707181541.l6IFf4ht051775@lurza.secnetix.de> <20070718170559.GA11915@eos.sc1.parodius.com> <20070719.084821.-202614780.imp@bsdimp.com>
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--nextPart4576160.1lHOmQfbd2 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline On Thursday 19 July 2007, M. Warner Losh wrote: > In message: <20070718170559.GA11915@eos.sc1.parodius.com> > > Jeremy Chadwick <koitsu@freebsd.org> writes: > : If someone wants to work on this and needs devices/toys (thumb > : drives, external enclosures + hard disks), let me know, I will be > : more than happy to buy them the hardware needed. > > Willing to fund the work on it too? This is a volunteer project, > and you have to motivate people to work on this. Tirades in > mailing lists has proven to be ineffective in the past. > > I've looked at the issue, and generically, if a device goes away, > it is *HARD* to not panic. The same thing happens if you eject a > CF card in a PC Card adapter in a PC Card slot. > > The best one can do without massive buffer cache work is what > firewire does: it has one attachment to handle all umass devices.=20 > When the device goes away, it pauses all operations to that device. > If the device comes back, it resumes the I/O . If the device > never comes back, then the I/O never finishes. > > Warner > Just curious, but what, if any, is the performance hit with this=20 strategy? I could care less about performance on a usb stick, but if=20 we are talking about changes that are going to affect all filesystems=20 regardless of storage device implimentation then I'm sort of=20 interested. eg: I wouldn't be happy trading filesystem performance for avoiding a=20 panic that is trivial to avoid in the first place. =2D-=20 Thanks, Josh Paetzel --nextPart4576160.1lHOmQfbd2 Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.4 (FreeBSD) iD8DBQBGn5OyJvkB8SevrssRAsqXAJ98RETmGzxIBmt2SiBB5zt0S3dnSACfXHkp ci5jccivyKEhONXAHppH+4Y= =bgmg -----END PGP SIGNATURE----- --nextPart4576160.1lHOmQfbd2--
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