From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg KH Date: Sat, 08 Nov 2003 22:25:29 +0000 Subject: Re: Accessing device information in REMOVE agent Message-Id: List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-hotplug@vger.kernel.org On Sat, Nov 08, 2003 at 04:02:25PM +0300, Andrey Borzenkov wrote: > I'd like to be notified when block device goes away (e.g. USB stick unplugged) > basically to look if device is in use and possibly initiate clean up. Block > hotplug currently is passing only DEVPATH; but it alone is not reliable way > to identify it; device may be used under alias names via symbolic links. What do you mean? DEVPATH is unique for that point in time. There are no alias's in sysfs. > Is it safe to access /sys/$DEVPATH in REMOVE agent? Apparently hotplug is > called asynchronously i.e. it is possible that /sys entry is already removed? The /sys entry is probably already removed, but if not, it will disappear any second. So no, it's not safe to try to access it, as it will not work. > Would it make sense to add device number? It seems to be natural native "block > device ID" :) What "device number"? The major/minor? Why? It's about as unique as DEVPATH is for any point in time. thanks, greg k-h ------------------------------------------------------- This SF.Net email sponsored by: ApacheCon 2003, 16-19 November in Las Vegas. Learn firsthand the latest developments in Apache, PHP, Perl, XML, Java, MySQL, WebDAV, and more! http://www.apachecon.com/ _______________________________________________ Linux-hotplug-devel mailing list http://linux-hotplug.sourceforge.net Linux-hotplug-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-hotplug-devel