From mboxrd@z Thu Jan 1 00:00:00 1970 From: Olaf Hering Date: Wed, 07 Jan 2004 20:52:37 +0000 Subject: Re: removable media revalidation - udev vs. devfs or static /dev Message-Id: <20040107205237.GB16832@suse.de> List-Id: References: <200401012333.04930.arvidjaar@mail.ru> <20040103055847.GC5306@kroah.com> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="macroman" Content-Transfer-Encoding: base64 To: Linus Torvalds Cc: Greg KH , Andrey Borzenkov , linux-hotplug-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org IE9uIFdlZCwgSmFuIDA3LCBMaW51cyBUb3J2YWxkcyB3cm90ZToKCj4gCj4gCj4gT24gRnJpLCAy IEphbiAyMDA0LCBHcmVnIEtIIHdyb3RlOgo+ID4gCj4gPiBEb2Vzbid0IHRoZSBrZXJuZWwgYWx3 YXlzIGNyZWF0ZSB0aGUgbWFpbiBibG9jayBkZXZpY2UgZm9yIHRoaXMgZGV2aWNlPwo+ID4gSWYg c28sIHVkZXYgd2lsbCBjYXRjaCB0aGF0Lgo+IAo+IEJ1dCB1ZGV2IHNob3VsZCBwcm9iYWJseSBh bHNvIGNyZWF0ZSBhbGwgdGhlIHN1Yi1ub2RlcyBpZiBpdCBkb2Vzbid0IAo+IGFscmVhZHkuCj4g Cj4gQW5kIGl0IHJlYWxseSBoYXMgdG8gY3JlYXRlIF9hbGxfIG9mIHRoZW0sIGV4YWN0bHkgYmVj YXVzZSB0aGVyZSdzIG5vIHdheQo+IHRvIGtub3cgYWhlYWQtb2YtdGltZSB3aGljaCBvZiB0aGVt IHdpbGwgYmUgYXZhaWxhYmxlLgo+IAo+IFRoZW4sIHVzZXIgc3BhY2UgY2FuIGp1c3QgYWNjZXNz ICIvZGV2L3NkYTEiIG9yIHdoYXRldmVyLCBhbmQgdGhlIGFjdCBvZiAKPiBhY2Nlc3NpbmcgaXQg d2lsbCBmb3JjZSB0aGUgcmUtc2Nhbi4KCkhvdyB3b3VsZCB0aGF0IHdvcms/IEkgbWVhbiwgd2hh dCB3aWxsIGEgdG9vbCB0aGF0IGNhcmVzIGFib3V0IGEgYmxvY2sKZXZlbnQgZG8/IEl0IHdpbGwg cnVuIGEgZmRpc2svcGFydGVkIC1sIC91ZGV2L3NkYSB0byBmaWd1cmUgb3V0IHdoYXQgcGFydGl0 aW9ucwphcmUgdGhlcmUgKGp1c3QgdG8gc2tpcCBhbiBleHRlbmRlZCBwYXJ0aXRpb24gc2RhNSwg YXMgZXhhbXBsZSkgYW5kCmZpbmRzIG5vIG1lZGlhLiBUaGF0IHRvb2wgd2lsbCBuZXZlciBydW4g YWdhaW4gb24gc2RhLCB1bmxlc3MgYSBuZXcKYmxvY2sgYWRkIGV2ZW50IGNvbWVzIGluLiBTbyBz b21lIHNvcnQgb2YgcG9sbGluZyBpcyByZXF1aXJlZCBmb3IgdGhhdApjbGFzcyBvZiBkZXZpY2Vz LgoKSWYgd2UgY3JlYXRlIHNkYTEgLSBzZGExNSwgeW91IG1lYW4gYSBtb3VudCAvdWRldi9zZGEx NSAvbW50IGlzIHN1cHBvc2VkCnRvIGZhaWwgd2l0aCAtRU5PREVWIGluc3RlYWQgb2YgLUVOT0VO VD8gCgotLSAKVVNCIGlzIGZvciBtaWNlLCBGaXJlV2lyZSBpcyBmb3IgbWVuIQoKc1VzZSBsSU5V WCBhZywgbsOcUk5CRVJHCgoKLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0t LS0tLS0tLS0tLS0tLS0tLQpUaGlzIFNGLm5ldCBlbWFpbCBpcyBzcG9uc29yZWQgYnk6IFBlcmZv cmNlIFNvZnR3YXJlLgpQZXJmb3JjZSBpcyB0aGUgRmFzdCBTb2Z0d2FyZSBDb25maWd1cmF0aW9u IE1hbmFnZW1lbnQgU3lzdGVtIG9mZmVyaW5nCmFkdmFuY2VkIGJyYW5jaGluZyBjYXBhYmlsaXRp ZXMgYW5kIGF0b21pYyBjaGFuZ2VzIG9uIDUwKyBwbGF0Zm9ybXMuCkZyZWUgRXZhbCEgaHR0cDov L3d3dy5wZXJmb3JjZS5jb20vcGVyZm9yY2UvbG9hZHByb2cuaHRtbApfX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fXwpMaW51eC1ob3RwbHVnLWRldmVsIG1haWxp bmcgbGlzdCAgaHR0cDovL2xpbnV4LWhvdHBsdWcuc291cmNlZm9yZ2UubmV0CkxpbnV4LWhvdHBs dWctZGV2ZWxAbGlzdHMuc291cmNlZm9yZ2UubmV0Cmh0dHBzOi8vbGlzdHMuc291cmNlZm9yZ2Uu bmV0L2xpc3RzL2xpc3RpbmZvL2xpbnV4LWhvdHBsdWctZGV2ZWw= From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265612AbUAGUxF (ORCPT ); Wed, 7 Jan 2004 15:53:05 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265619AbUAGUxF (ORCPT ); Wed, 7 Jan 2004 15:53:05 -0500 Received: from ns.suse.de ([195.135.220.2]:42216 "EHLO Cantor.suse.de") by vger.kernel.org with ESMTP id S265612AbUAGUwv (ORCPT ); Wed, 7 Jan 2004 15:52:51 -0500 Date: Wed, 7 Jan 2004 21:52:37 +0100 From: Olaf Hering To: Linus Torvalds Cc: Greg KH , Andrey Borzenkov , linux-hotplug-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org Subject: Re: removable media revalidation - udev vs. devfs or static /dev Message-ID: <20040107205237.GB16832@suse.de> References: <200401012333.04930.arvidjaar@mail.ru> <20040103055847.GC5306@kroah.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-DOS: I got your 640K Real Mode Right Here Buddy! X-Homeland-Security: You are not supposed to read this line! You are a terrorist! User-Agent: Mutt und vi sind doch schneller als Notes Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 07, Linus Torvalds wrote: > > > On Fri, 2 Jan 2004, Greg KH wrote: > > > > Doesn't the kernel always create the main block device for this device? > > If so, udev will catch that. > > But udev should probably also create all the sub-nodes if it doesn't > already. > > And it really has to create _all_ of them, exactly because there's no way > to know ahead-of-time which of them will be available. > > Then, user space can just access "/dev/sda1" or whatever, and the act of > accessing it will force the re-scan. How would that work? I mean, what will a tool that cares about a block event do? It will run a fdisk/parted -l /udev/sda to figure out what partitions are there (just to skip an extended partition sda5, as example) and finds no media. That tool will never run again on sda, unless a new block add event comes in. So some sort of polling is required for that class of devices. If we create sda1 - sda15, you mean a mount /udev/sda15 /mnt is supposed to fail with -ENODEV instead of -ENOENT? -- USB is for mice, FireWire is for men! sUse lINUX ag, nÜRNBERG